Category: 2199-44-2

Category: thiazolidine. So far, in addition to halogen atoms, other non-metallic atoms can become part of the aromatic heterocycle, and the target ring system is still aromatic. Compound: Ethyl 3,5-Dimethyl-2-pyrrolecarboxylate, is researched, Molecular C9H13NO2, CAS is 2199-44-2, about Some mercuration reactions of substituted pyrroles.

Mercuration of N-unsubstituted pyrroles with mercury(II) acetate results in immediate precipitation of the N-mercurated derivative, which is insoluble in virtually all organic solvents. If the pyrrole N atom is protected (e.g. with Me, CH2OCH2Ph, or CO2CMe3) then mercuration takes place efficiently at unsubstituted pyrrole carbons. Subsequent palladium/olefin (Heck-type) reactions afford the corresponding pyrrole acrylate when, for example, the olefin is Me acrylate; deprotection (when the N-substituent is CH2OCH2Ph or CO2CMe3) then affords the required carbon-substituted pyrrole. Attempts to deprotect the N-methylpyrroles were unsuccessful.

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HPLC of Formula: 2199-44-2. Aromatic heterocyclic compounds can also be classified according to the number of heteroatoms contained in the heterocycle: single heteroatom, two heteroatoms, three heteroatoms and four heteroatoms. Compound: Ethyl 3,5-Dimethyl-2-pyrrolecarboxylate, is researched, Molecular C9H13NO2, CAS is 2199-44-2, about Double-helical dinuclear bis(dipyrromethene) complexes Formed by self-assembly. Author is Thompson, Alison; Dolphin, David.

Bis(dipyrromethene) ligands linked by an alkyl spacer between β and β’ positions (I; n = 1, 2, 3) give helical dimers or monomers, dependent upon the length of the alkyl linker, upon complexation. Ligands consisting of methylene, ethylene, and propylene linkers -(CH2)n- (n = 1, 2, and 3) give helical dimers, while longer linking chains (n = 4, 5, or 6) give monomers or mixtures of dimers and monomers. X-ray crystal structures of the dimeric Zn complexes (n = 1, 2, and 3) reveal that the angles between dipyrromethene planes and the extent of helicity in the complexes differ as the length of the linker varies. The extent of helicity was assessed and is dependent upon the length and, specifically, the conformational preferences of the alkyl spacer unit. The presence of an ethylene linker gave complexes of greatest helicity. The use of a methylene spacer gave less helical structures upon complexation, while propylene spacers gave only slightly helical complexes. These studies identify the crucial importance that the conformational preferences of the β-β’ alkyl spacer group plays in the coordination algorithm of self-assembly to form dipyrromethene based complexes.

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Reference of Ethyl 3,5-Dimethyl-2-pyrrolecarboxylate. Aromatic heterocyclic compounds can also be classified according to the number of heteroatoms contained in the heterocycle: single heteroatom, two heteroatoms, three heteroatoms and four heteroatoms. Compound: Ethyl 3,5-Dimethyl-2-pyrrolecarboxylate, is researched, Molecular C9H13NO2, CAS is 2199-44-2, about Synthesis and spectral analysis of alkyl-substituted 3,3′-bis(dipyrrolylmethenes). Author is Antina, E. V.; Guseva, G. B.; Dudina, N. A.; V’yugin, A. I.; Semeikin, A. S..

Four new alkyl-substituted 3,3′-bis(dipyrrolylmethene) dihydrobromide derivatives containing from 4-10 alkyl substituents were synthesized. In a highly alkylated ligand among these substances one of the hydrogen atoms of the 3,3′-methylene spacer was substituted with a Ph group. The compounds obtained were studied by IR, 1H NMR, electron absorption and fluorescent spectroscopy. The increased alkylation degree of pyrroles and the introduction of an aryl substituent in the 3,3′-spacer causes a significant high-frequency shift of the N-H stretching vibrations in the IR spectra, an upfield shift of the NH-proton signals in NMR spectra, a decrease in the auxochromic effects of protons on the aromatic system of chromophore in the composition of salts. The red shift of maximum of the strong band in electron absorption spectra and the emission spectra of compounds in DMF, DMSO, C5H5N, C6H6, and CHCl3 was established. The salts obtained are stable in benzene and chloroform, while in electron-donor solvents the irreversible processes of solvolytic dissociation of salts to free organic base and HBr take place.

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The reaction of an aromatic heterocycle with a proton is called a protonation. One of articles about this theory is 《Perylene and its derivatives. XLIX. The perylene trihalides of K. Brass and E. Clar》. Authors are Zinke, A.; Pongratz, A.; Scholtis, K.; Hanus, F..The article about the compound:Ethyl 3,5-Dimethyl-2-pyrrolecarboxylatecas:2199-44-2,SMILESS:O=C(C1=C(C)C=C(C)N1)OCC).Formula: C9H13NO2. Through the article, more information about this compound (cas:2199-44-2) is conveyed.

cf. C. A. 30, 6362.7. It had been shown that Brass and Clar’s “”perylene tribromide”” (C. A. 27, 720) is not a substance of constant composition and that the primary product of the action of Br on perylene is rather a tetrabromide. In a reply, B. and C. (C. A. 30, 6735.3) lay stress on the constancy in composition of their tribromide and deplore the fact that Z. and P. give the results of only 1 of the numerous analyses of their Br product. To meet this criticism a number of further bomb determinations are reported, although the authors believe their earlier data suffice to establish their contention. B. and C. also doubt the constancy of the composition of the tetrabromide and believe the higher Br values obtained by Z. and P. are due to the fact that they did not remove the excess of Br at an elevated temperature Some determinations are now reported in which the excess Br was removed with a current of warm (50-60°) air; they, too, show distinctly that 4 atoms Br are first taken up. Repeated treatment of the product with warm air showed that the loss in weight is at first due almost exclusively to evaporation of the mechanically attached Br, and when this ceases to be given off the compound has the composition of a tetrabromide. Further loss of Br as HBr occurs at an appreciably slower rate; a preparation kept in a desiccator for hrs. still contained considerably more Br than the amount calculated for a tribromide. The substance prepared by the action of I on perylene in hot benzene according to the (very incomplete) directions of B. and C. likewise has not a constant composition and was always found to contain more I than that calculated for a triiodide; the I content of the beautifully crystalline product depended on the concentration and the total amount of I dissolved in the benzene.

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The preparation of ester heterocycles mostly uses heteroatoms as nucleophilic sites, which are achieved by intramolecular substitution or addition reactions. Compound: Ethyl 3,5-Dimethyl-2-pyrrolecarboxylate( cas:2199-44-2 ) is researched.Application In Synthesis of Ethyl 3,5-Dimethyl-2-pyrrolecarboxylate.Tu, Bin; Wang, Changqi; Ma, Jinshi published the article 《New method for synthesis of (ω-chloroalkyl)pyrroles》 about this compound( cas:2199-44-2 ) in Organic Preparations and Procedures International. Keywords: chloroalkylpyrrolecarboxylate preparation; pyrrole chloroalkyl derivative preparation. Let’s learn more about this compound (cas:2199-44-2).

Et 4-(ω-chloroalkyl)-3,5-dimethyl-1H-pyrrole-2-carboxylates (alkyl = Et, Pr, butyl) were prepared in >96% yields from Et 4-(ω-chloroacyl)-3,5-dimethyl-1H-pyrrole-2-carboxylates by treatment with NaBH4 followed by BF3·Et2O in THF. The ω-chloroacyl derivatives were prepared from 2-(ethoxycarbonyl)-3,5-dimethylpyrrole (1) by Friedel-Crafts reaction in >91% yields. 1 Was prepared in one step from 2,4-pentanedione and di-Et aminomalonate or di-Et oximinomalonate according to literature methods.

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Most of the compounds have physiologically active properties, and their biological properties are often attributed to the heteroatoms contained in their molecules, and most of these heteroatoms also appear in cyclic structures. A Journal, Atti accad. sci. ist. Bologna, Classe sci. fis. called Synthesis of pyrrolecarboxaldehydes, Author is Ghigi, Elisa; Drusiani, Annamaria, which mentions a compound: 2199-44-2, SMILESS is O=C(C1=C(C)C=C(C)N1)OCC, Molecular C9H13NO2, Reference of Ethyl 3,5-Dimethyl-2-pyrrolecarboxylate.

HCO-NMe2 (I) (23.89 g.) and 58.25 g. POCl3 warmed after 10 min. to 60°, treated dropwise in 1.5 hrs. with 18 g. 2,4-dimethylpyrrole in an equal volume of I, the mixture stirred 1 hr. at 60°, poured into 333 g. ice and 245 g. fused NaOAc, the mixture boiled, cooled, extracted with Et2O, the extract evaporated free from Et2O and made alk. with powd. Na2CO3, filtered, and the residual product (II) dried. Further extraction of the filtrate with Et2O gave another 0.69 g. II. II boiled in petr. ether, the solution purified with C, filtered and cooled gave 0.6 g. (crude) 2,4-dimethyl-3,5-pyrroledicarboxaldehyde, m. 165-6° (from H2O), and 9.6 g. (crude) 2,4-dimethyl-5-pyrrolecarboxaldehyde, m. 89-90° (from H2O). Similarly, I and POCl3 at 60°, treated dropwise with stirring with 2,4-dimethyl-8-ethylpyrrole gave 2,4-dimethyl-3-ethyl-5-pyrrolecarboxaldehyde, m. 105-6°. In the same way, 1.79 g. I and 4.37 g. POCl3 treated with 1.35 g. 2,3,4-trimethylpyrrole gave 0.3 g. 2,3,4-trimethyl-5-pyrrolecarboxaldehyde, m. 147°; 2.6 g. I and 6.32 g. POCl3 with 3 g. Et 2,4-dimethyl-3-pyrrolecarboxylate in I yielded Et 2,4-dimethyl-5-formyl-3-pyrrolecarboxylate, m. 165°; 8.6 g. I and 21 g. POCl3 with 10 g. Et 2,4-dimethyl-5-pyrrolecarboxylate and 10 g. I produced 11.2 g. Et 2,4-dimethyl-3-formyl-5-pyrrolecarboxylate, m. 145°. Heating 20 g. 2,4-dimethyl-5-carbethoxy-3-pyrrolecarboxylate at 200° with 200 g. quinoline and 2 g. finely divided pure Cu to cessation of CO2 evolution, cooling, filtering, acidifying the filtrate with 50% HCl, filtering, washing the precipitate with H2O, and drying gave 11.2 g. Et 2,4-dimethyl-5-pyrrolecarboxylic acid, m. 122°.

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Reference of Ethyl 3,5-Dimethyl-2-pyrrolecarboxylate. Aromatic compounds can be divided into two categories: single heterocycles and fused heterocycles. Compound: Ethyl 3,5-Dimethyl-2-pyrrolecarboxylate, is researched, Molecular C9H13NO2, CAS is 2199-44-2, about Detection and Prevention of Aggregation-based False Positives in STD-NMR-based Fragment Screening. Author is Vom, Amelia; Headey, Stephen; Wang, Geqing; Capuano, Ben; Yuriev, Elizabeth; Scanlon, Martin J.; Simpson, Jamie S..

Aggregation of small organic compounds is a problem encountered in a variety of assay screening formats where it often results in detection of false positives. A saturation transfer difference-NMR-detected screen of a com. available fragment library, followed by biochem. assay, identified several inhibitors of the enzyme ketopantoate reductase. These inhibitors were subsequently revealed to be aggregation-based false positives. Modification of the fragment screen by addition of detergent in the saturation transfer difference-NMR experiments allowed an assay format to be developed that resulted in the identification of genuine hit mols. suitable for further development.

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Recommanded Product: Ethyl 3,5-Dimethyl-2-pyrrolecarboxylate. Aromatic heterocyclic compounds can also be classified according to the number of heteroatoms contained in the heterocycle: single heteroatom, two heteroatoms, three heteroatoms and four heteroatoms. Compound: Ethyl 3,5-Dimethyl-2-pyrrolecarboxylate, is researched, Molecular C9H13NO2, CAS is 2199-44-2, about Automated Microflow NMR: Routine Analysis of Five-Microliter Samples. Author is Jansma, Ariane; Chuan, Tiffany; Albrecht, Robert W.; Olson, Dean L.; Peck, Timothy L.; Geierstanger, Bernhard H..

A microflow CapNMR probe double-tuned for 1H and 13C was installed on a 400-MHz NMR spectrometer and interfaced to an automated liquid handler. Individual samples dissolved in DMSO-d6 are submitted for NMR anal. in vials containing as little as 10 μL of sample. Sets of samples are submitted in a low-volume 384-well plate. Of the 10 μL of sample per well, as with vials, 5 μL is injected into the microflow NMR probe for anal. For quality control of chem. libraries, 1D NMR spectra are acquired under full automation from 384-well plates on as many as 130 compounds within 24 h using 128 scans per spectrum and a sample-to-sample cycle time of ∼11 min. Because of the low volume requirements and high mass sensitivity of the microflow NMR system, 30 nmol of a typical small mol. is sufficient to obtain high-quality, well-resolved, 1D proton or 2D COSY NMR spectra in ∼6 or 20 min of data acquisition time per experiment, resp. Implementation of pulse programs with automated solvent peak identification and suppression allow for reliable data collection, even for samples submitted in fully protonated DMSO. The automated microflow NMR system is controlled and monitored using web-based software.

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Quality Control of Ethyl 3,5-Dimethyl-2-pyrrolecarboxylate. Aromatic compounds can be divided into two categories: single heterocycles and fused heterocycles. Compound: Ethyl 3,5-Dimethyl-2-pyrrolecarboxylate, is researched, Molecular C9H13NO2, CAS is 2199-44-2, about Acetylene condensation in a series of pyrroles. Author is Sundukova, T. A.; Vasilevskii, S. F.; Shvartsberg, M. S.; Kotlyarevskii, I. L..

Condensation of Et 4-iodo-3,5-dimethylpyrrole-2-carboxylate with HCCR(R = Ph, morpholinomethyl) in Et2NH in the presence of Pd (PPh3)2Cl2 and CuI gave ethynylpyrroles I in 64 and 68% yield, resp. Similar reaction with HOCMe2CCH gave the deiodinated product in 18% yield. Treatment of II (R = I) with CuCCPh in pyridine-DMF at reflux gave 78.0% II (R = CCPh). Deiodination of III (R = I) (IV) was easier than with the 4-iodo-2-carboxylate derivative but more difficult than II (R = I). In the presence of Pd complex catalyst condensation of IV and PhCCH gave concurrent redn and substitution.

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The reaction of an aromatic heterocycle with a proton is called a protonation. One of articles about this theory is 《Iodo derivatives of pyrroles》. Authors are Treibs, Alfred; Kolm, Hans Georg.The article about the compound:Ethyl 3,5-Dimethyl-2-pyrrolecarboxylatecas:2199-44-2,SMILESS:O=C(C1=C(C)C=C(C)N1)OCC).Computed Properties of C9H13NO2. Through the article, more information about this compound (cas:2199-44-2) is conveyed.

Although iodo derivatives of pyrrole are quite stable to alkali, the iodine is rather easily replaced by H, Br, Cl, aryl azo, NO2, and CHR groups. Nitropyrroles are prepared almost exclusively by replacing other substituents by the NO2 group. To 6.7 g. pyrrole and 66 g. KI in 400 cc. 25% EtOH at 30° was added 28 g. AcOH, 10 g. AcONa, 38 cc. 10% H2O2, and 50 cc. H2O; the resulting exothermic reaction was kept 20 min. at 45° giving 2,3,4,5-tetraiodopyrrole, m. 162-4° (decomposition) (EtOH). 2,4-Dimethylpyrrole (I) (3 g.) in 100 cc. MeOH and 9 g. K2CO3 in 100 cc. H2O with 64 cc. M KI3 was shaken until colorless and diluted gradually with H2O to give 9.7 g. 3,5-diiodo derivative (II) of I, m. 83° (aqueous MeOH followed by petr. ether), stable for only 1-2 days. I in EtOH and AcOH with KI3 gave a dark oil yielding only 3-8% II. Formed similarly to II was 2,5-dimethyl-3,4-diiodopyrrole, m. 132°, decompose 135-45° (petr. ether containing Et2O followed by vacuum sublimation), very sensitive to light, especially in solution To 1.75 g. 1,2,5-trimethytpyrrole (III) in 125 cc. MeOH and 10 g. K2CO3 in 50 cc. H2O at -10° was added dropwise 16 cc. M KI3, the mixture kept colorless, filtered promptly from a brown precipitate, and evaporated in vacuo; the residue in petr. ether refiltered and evaporated gave 2.7 g. 3-iodo derivative (IV) of III, m. 71° (MeOH or sublimation), decompose within 30 min. in daylight, stable 1-2 days under extreme precautions. III (1 g.) and 10 g. K2CO3 in 180 cc. 60% MeOH treated in 1 portion with 4.6 g. iodine in 50 cc. MeOH gave 3.2 g. 4-iodo derivative of IV, pale yellow, m. 129° (dilute EtOH). Formed similarly to IV from 2,3,4-trimethylpyrrole (V) (using iodine in MeOH), was the 5-iodo derivative of V, m. 90° (petr. ether at -70°), giving a pos. Ehrlich reaction at 20°, decomposing readily in warm solution From 3-formyl derivative of I in alk. MeOH was formed 90.4% 3-formyl-5-iodo derivative of I, m. 157° (MeOH), also prepared in similar yield by treating 2.5 g. 3-formyl derivative of I in 20 cc. EtOH with 3 g. AcONa and 2.3 g. H2O2, acidifying with 2 g. AcOH at 40-50°, and adding 2.3 g. KI in H2O. By either of these methods, the 5-formyl derivative of I gave 84-6% 3-iodo-5-formyl derivative of I, m. 172° (EtOH). In alk. MeOH containing KI3 and in AcOHMeOH with KI and 3% H2O2 2-methyl-3-carbethoxypyrrole (VI) gave 90-94% 4,5-diiodo derivative of VI, pale pink, m. 191° (decomposition) (when rapidly heated). From 2 g. 3-methyl-2,4-dicarbethoxypyrrole (VII) in 30 cc. 50% EtOH at 80° with 8.9 cc. M KI3 (gradually added) was formed 2.8 g. 5-iodo derivative (VIII) of VII, m. 174° (EtOH), also prepared by Kleinspehn and Corwin’s method (C.A. 49, 285g); under these conditions a hitherto undescribed very insoluble dark green iodine adduct of VIII (not analyzed) was also formed. The 5-carbethoxy derivative of I in acid solution by the usual procedures gave 98% 3-iodo-5-carbethoxy derivative (IX) of I, nacreous leaflets, m. 141°, also formed from the 3-carboxy analog of IX by iodination and decarboxylation. IX heated with alk. MeOH gave the 5-CO2Me analog of IX, m. 182°. Formed by the usual procedures from the 3-carbethoxy derivative of I or its 5-carboxy derivative was the 3-carbethoxy-5-iodo derivative (IXa) of I, m. 146°. IX stirred with KOH at 135-40° and acidified with HCl gave 3-iodo-5-carboxy derivative of I, m. 112° (decomposition), giving a pos. Ehrlich reaction; this could not be converted into the 3-iodo derivative of I by thermal decarboxylation. To 3.94 g. of the product formed by condensing VI with BzH (Fischer and Schubert, C.A. 21, 381) in 50 cc. MeOH and 3 g. K2CO3 in 10 cc. H2O was added gradually 20 cc. M KI3 and the mixture boiled briefly giving (HN.CHMe:CR.CI:C)2CHR’ (X) (R = CO2Et, R’ = Ph), m. 217-18° (decomposition) (when rapidly heated). Formed analogously was X (R = CO2Et, R’ = Me), m. 168° (decomposition) (MeOH). In either case X was identified by coupling with p-O2NC6H4N2OAc and subsequent fission giving p-O2C6H4N:NC:CI.CR:CHMe.NH (Xa) (R = CO2Et) (cf. C.A. 52, 13705g). The 4,5-diiodo derivative of VI refluxed with 0.5 g. NH4Cl and 15 cc. 80% EtOH with gradual addition of 0.3 g. Zn dust, filtered, and treated with 75 cc. H2O containing little NH4OH or HCl gave VI, m. 72°. This method failed to remove iodine from the 5-iodo derivative of VII, which however with Zn in warm glacial AcOH gave VII, m. 91°. Under similar conditions the 5-Br derivative of VII remained unchanged. The 4-iodo-5-nitro derivative (Xb) of VI (0.65 g.) refluxed 30 min. with 0.32 g. Natur-kupfer C and 15 cc. glacial AcOH, filtered hot, and treated with 10% HCl gave 90% 5-NO2 derivative of VI, m. 144°, giving deep yellow alk. solutions, yielding pale yellow needles on acidification, giving no Ehrlich reaction and extremely unreactive. The following could be reduced similarly by means of the same catalyst: IX, the 5-iodo derivative of VII, and the 4,5-iodo derivative of VI. None of the corresponding Br derivatives was affected by this catalyst. IX (0.3 g.) in 5 cc. Ac2O warmed gently with 0.8 g. KI did not react until small amounts of H2O were added to the hot solution followed by cold H2O, whereupon a mixture of IX and the 5-CO2Et derivative of I was formed. On long standing the amounts of IX increased, but in the presence of NaHSO3 the yield of 5-CO2Et derivative of I was quant. In the above reaction KBr could replace KI, but KCl or NH4Cl were inactive unless IX was prehydrolyzed with HCl. The 3-iodo-5-carboxy derivative of I warmed with dilute HCl, made alk. with NaOH, and extracted with Et2O gave I (picrate, m. 90°). IX in 10 cc. 70% Et2O treated with BF3, poured on ice, and neutralized with Na2CO3 gave mostly black products and little I. In the presence of Cu, BF3-Et2O reacted with IX at 50° giving 5-CO2Et derivative of I, m. 122°. IXa with equimolar amounts of Ph3P in dry Et2O after 2 hrs. gave unanalyzed yellow crystals (XI), m. 218° (N-free), the filtrate from which gave the 3-CO2Et derivative of I, m. 75°. IX gave a similar reaction with Ph3P but required 2 weeks to give XI; the filtrate gave the 5-CO2Et derivative of I. In 100-200 mg. of various iodo- and bromopyrroles, the % halogen could be determined by treating with equal amounts of KI in 50-80 cc. 80% MeOH at 50-60°, acidifying with 2N H2SO4, and titrating with 0.1N Na2S2O3. Usually the results were satisfactory. However the iodo derivatives of VII and X reacted so slowly with hot methanolic KI solutions that the method could not be used. A technique for the qual. identification of iodine in pyrrole derivatives is described. To 0.5 g. 3,5-di-CO2Et derivative of I in 30 cc. MeOH at 0° 1 g. iodine in MeOH was added gradually and the mixture poured into 400 cc. ice-cold 1% aqueous KI giving the deep blue adduct C12H17NO4.I, m. 146° (after washing with H2O and drying rapidly over P2O5), which in hot EtOH gave the original pyrrole, m. 137°. Similarly, the 5-Bt derivative of VII gave the adduct C11H14BrNO4.I, m. 152-4°, decolorized at 60° by aqueous alcoholic KI, but giving the adduct on cooling. Similar (undescribed) iodine adducts were obtained with pyrrole, VII, and the 5-CO2H derivative of VII; the latter on heating in alk. solution gave VIII. IX (4 g.) was added gradually to 30 cc. concentrated HNO3 at 0°, kept 1 hr., the precipitate washed with H2O and triturated with little aqueous NaHCO3, and extracted with 2 g. KI; the residue gave 2.5 g. 3-nitro-5-carbethoxy derivative (XII) of I, m. 204° (CHCl3); the corresponding 5-CO2Me analog, m. 184°. XII (65%) was also formed by adding the 5-CO2Et derivative of I at 0° to HNO3 and after 10 hrs. pouring into ice H2O. From IXa and HNO3 at -10° was formed 55% 3-carbethoxy-5-nitro derivative of I, m. 149° (dilute EtOH), identical with the compound obtained by Fischer and Zerweck (C.A. 17, 106). From the 4,5-diiodo derivative of VI and HNO3 was formed 75% Xb, m. 181°, and from VIII was formed the 5-NO2 derivative of VII, pale yellow, m. 111° (ligroine). The 4,5-diiodo derivative of VI (0.5 g.) in 30 cc. glacial AcOH with 0.24 g. p-O2NC6H4N2OAc in 5 cc. AcOH gave Xa, orange red, m. 186-7° (decomposition) (EtOH), soluble in MeOH containing NaOH, reprecipitated with acid. Similarly the 4-iodo derivative of IV gave 1,2,5-trimethyl-3-iodo-4-(p-nitrophenylazo)pyrrole, brown needles, sintering 160°, m. 185° (decomposition), 2,3,4,5-Tetraiodopyrrole similarly gave 2,3,4-triiodo-5-(p-nitrophenylazo)pyrrole, red, m. 221° (decomposition), giving a violet solution in alk. MeOH, reprecipitated by HCl. No azo dye was isolated by similar treatment of the 3-formyl-5-iodo and 5-formyl-3-iodo derivatives of I, X, or the 5-NO2 derivative of VI. IXa (2.9 g.) in 25 cc. EtOH was boiled briefly with 0.5 cc. 30% HCHO and 1 cc. concentrated HCl added dropwise giving bis(2,4-dimethyl-3-carbethoxy-5-pyrryl)methene-HCl, red with blue surface luster, m. 224° (cf. Fischer and Zerweck, C.A. 17, 1465), which in boiling EtOH with NH4OH gave the corresponding free methene (XIII), yellow, m. 190°. IXa treated as above, but in cold MeOH, with HCHO and a drop of 2N HCl and after 15 hrs. made barely alk. with 2N NaOH and crystallized from MeOH gave a mixture which was fractionated from CHCl3 giving 18% less soluble bis(2,4-dimethyl-3-carbethoxy-5-pyrryl)methane (XIIIa), m. 224°, whose mother liquor gave 73% XIII. IXa (2.9 g.) in 25 cc. hot EtOH with 0.5 cc. 30% HCHO was heated with 5 g. Na2S2O3 in 15 cc. H2O and acidified with HCl to pH 3. The precipitate was triturated with hot EtOH containing little NaOH and filtered giving XIIIa and from the mother liquor bis(2,4-dimethyl-3-carbethoxy-5-pyrryl) sulfide, C18H24N2O4S, m. 198-200° (slowly heated), 212° (rapid heating) (CHCl3-petr. ether followed by CCl4). IXa in EtOH with BzH and little HCl refluxed 30 min. and made alk. with dilute NH4OH gave 30% ms-phenylbis(2,4-dimethyl-3-carbethoxy-5-pyrryl)methene (XIV), orange-red, m. 158° (MeOH); HCl salt, m. 204°. Very similarly, IXa and 1,4-C6H4(CHO)2 in EtOH with a trace of concentrated HCl refluxed 10 min. gave a dark crystalline deposit which was triturated with 20% EtOH and warm H2O and treated with NH4OH giving p-phenylenebis [ms-bis(2,4-dimethyl-3-carbethoxy-5-pyrryl)methene], pale orange, turning black at 272° (CHCl3 and xylene), turning dark red on exposure to direct sunlight, which when treated with Zn and HCl in EtOH at 40° gave a colorless compound, m. 267° (putatively the corresponding methane, but not analyzed). By the usual procedure, IXa and p-Me2NC6H4CHO yielded ms-(p-dimethylaminophenyl)bis(2,4-dimethyl-3-carbethoxy-5-pyrryl)-methen-HCl, coarse dark crystals, m. 224-5° (even when the alcoholic solution was made alk. with NH4OH), which in 80% MeOH containing a little HCl treated with an excess 2N NaOH and heated gave the free methene, C27H33N3O4, red rodlets with green luster, m. 183°. XIIIa (70 mg.) in 20 cc. MeOH treated gradually with 68 mg. ICl in 2 cc. MeOH gave XIII. XIV was similarly formed from the corresponding methane. Tetrakis(2,4-dimethyl-3-carbethoxy-5-pyrryl)ethane and tris(2,4-dimethyl-3-carbethoxy-5-pyrryl)methane oxidized with ICl both gave XIII. IX (3 g.) in 20 cc. AcOH was boiled 20 min., treated with a mild stream of air, and distilled; any loss of AcOH was compensated for by AcOH addition H2O added to the distillate gave a dark precipitate which treated with C and fractionated from dilute EtOH gave principally the 5-CO2Et derivative of I, m. 122°, very small amounts of 3-Ac-5-CO2Et derivative of I, m. 142°, and after high vacuum sublimation at 120° [MeC:C(CO2Et).NH.CMe:C]2 (XV), m. 186°, showing a pale yellow-green fluorescence in EtOH, colorless in ligroine, giving no Ehrlich test, and forming no azo dye with p-O2NC6H4N2OAc in acid unless previously heated with alk. MeOH, after which both reactions were pos. An attempt to form a bipyrrole derivative analogous to XV by the deiodination of IXa gave an orangered compound, m. 254° (ligroine, CCl4, or CHCl3-Et2O), containing about 63% C, 6.6 H, and 8.0 N; the mother liquor gave 3-CO2Et derivative (XVI) of II, m. 76°. IXa in glacial AcOH with N Br in AcOH with addition of dilute Na2S2O3 gave the corresponding 5-Br analog (XVII) of IXa, m. 96° (decomposition) (when rapidly heated), m. 102° (decomposition), also formed by treating IXa in AcOH with concentrated aqueous HBr and crystallizing from dilute AcOH. When in this reaction excess Na2SO3 was added, XVI was obtained. IXa (200 mg.) in 4 cc. AcOH, 0.5 cc. concentrated HCl, a little H2O, and small amounts of Br followed by (but avoiding an excess of) Na2S2O3 gave the 5-Cl analog of IXa, m. 140° (decomposition) (aqueous MeOH or dilute AcOH), also formed from XVII. The 5-CO2Et derivative of I in AcOH with excess concentrated HCl and equivalent amounts of Br gave 5-CO2Et-3-Cl derivative of I, m. 182-3° (EtOH); 32 references.

In addition to the literature in the link below, there is a lot of literature about this compound(Ethyl 3,5-Dimethyl-2-pyrrolecarboxylate)Computed Properties of C9H13NO2, illustrating the importance and wide applicability of this compound(2199-44-2).

Reference:
Thiazolidine – Wikipedia,
Thiazolidine – ScienceDirect.com