Acetonitrile Acetylenedicarboxylic acid

With electron-deficient acetylenes, the dithioate anions can be involved in the reactions of both 1,3-anionic cyclo- and nucleophilic additions [550], The reactions of 1,3-anionic cycloaddition are typical provided that the central atom of [S-C-S] has aromatic substituents ensuring the anion stabilization [551,552], For instance, potassium pyrrole-l-carbodithioate selectively reacts (acetonitrile, -30°C, CH3COOH) with dimethyl ester of acetylenedicarboxylic acid to form rapidly polymerizing 2-(pyrrol-l-yl)-4,5-dimethoxycarbonyl-l,3-dithiol (Scheme 2.80) [552,553]. 

In the presence of a catalytic amount of concentrated hydrochloric acid, dimethyl 1 -methyl-1 H-l-benzazepine-3,4-dicarboxylate (1) undergoes addition of 1-methylindole, probably via initial protonation of the enaminic 3-position of the benzazepine ring, to give the indolyldihydrobenz-azepine 2.21 In fact, adduct 2 is the major product from the reaction of 1-mcthylindole with dimethyl acetylenedicarboxylate in acetonitrile. Similar adducts are obtained with indole. 

Pyrex-filtered irradiation in de-aerated acetonitrile solution. The resultant enols can be trapped by dimethyl maleate to yield the adducts (27) and (28) in the ratios and yields shown. Trapping of the enols can also be acomplished using dimethyl acetylenedicarboxylate or ethyl propiolate as the dienophile. A study of the phototautomerism of methyl salicylate (29) into (30) at 77 K has been carried out and this again involves a 1,5-hydrogen transfer. Interestingly, the authors report that triplet state emission occurs from the transient keto form (30). The influence of aryl substituents (p-Me and -MeO) upon the photochemically induced intramolecular proton transfer in salicylic acid has also been studied in detail. 

Acetic add, frons-cyclohexanediaminetetra-metal complexes, 554 Acetic add, ethylenediaminetetra-in analysis, 522 masking, 558 metal complexes, 554 Acetic acid, iminodi-metal complexes, 554 Acetic acid, nitrilotri-metal complexes titrimetry, 554 Acetoacetic add ethyl ester bromination, 419 Acetone, acetyl-deprotonation metal complexes, 419 metal complexes reactions, 422 Acetone, selenoyl-liquid-liquid extraction, 544 Acetone, thenoyltrifluoro-liquid-liquid extraction, 544 Acetone, trifluorothenoyl-in analysis, 523 Acetonitrile electrochemistry in, 493 exchange reactions, 286 metal complexes hydrolysis, 428 Acetylacetone complexes, 22 liquid-liquid extraction, 543 Acetylacetone, hexafiuorothio-metal complexes gas chromatography, 560 Acetylactone, trifluorothio-metal complexes gas chromatography, 560 Acetylation metal complexes, 421 Acetylenedicarboxylic add dimethyl ester cycloaddition reactions, 458 Acid alizarin black SN metallochromic indicator, 556 Actinoids... 

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