Transesterification of trimethyl orthoacetate: an efficient protocol for the synthesis of 4-alkoxy-2-aminothiophene-3-carbonitriles

Inorganic‐organic hybrid material based on amine‐functionalized zeolite Y: A study of catalytic activity in transesterification

“…However, the functionalized amine compound on zeolite Y catalyst has not been reported in organic synthesis. There are many organic reaction‐related alkali catalysts for studying the catalytic performance of amine‐functionalized zeolite Y. Transesterification is an important organic reaction related to alkali catalysts, and is an essential synthetic route for numerous organic chemicals . Products from transesterification, such as didodecyl carbonate, diphenyl carbonate, ethylene carbonate, bis(2‐hydroxyethyl)terephthalate, dimethyl carbonate, and glycerol carbonate can be used in many applications.…”

Green methodologies for the synthesis of 2-aminothiophene

“…In 2013, Venkata Rao and his team developed the synthesis of sixteen 3,4-substituted-2-aminothiophenes ( 28a – p ) from trimethyl orthoacetate 26 (Venkata Rao et al 2013 ). As described in Fig.…”

Expeditious Scalable Catalyst-Free One-Pot Synthesis of 4-Alkoxy-5-amino-3-methylthiophene-2-carbonitriles via Sequential Reactions­ of Lithiated Alkoxyallenes with Isothiocyanates and 2-Bromoacetonitrile

“…IR (neat): 3330, 3116, 3052, 2935IR (neat): 3330, 3116, 3052, , 2877IR (neat): 3330, 3116, 3052, , 2192IR (neat): 3330, 3116, 3052, (C≡N), 1620IR (neat): 3330, 3116, 3052, , 1565IR (neat): 3330, 3116, 3052, , 1498IR (neat): 3330, 3116, 3052, , 1460IR (neat): 3330, 3116, 3052, , 1410IR (neat): 3330, 3116, 3052, , 1348IR (neat): 3330, 3116, 3052, , 1321IR (neat): 3330, 3116, 3052, , 1272IR (neat): 3330, 3116, 3052, , 1243IR (neat): 3330, 3116, 3052, , 1195IR (neat): 3330, 3116, 3052, , 1128IR (neat): 3330, 3116, 3052, , 1106IR (neat): 3330, 3116, 3052, , 1088IR (neat): 3330, 3116, 3052, , 1022 The 1 H-13 C HMBC and 1 H-13 C HSQC 2D experiments provided additional support for the proposed structure. 13), 181 (25), 180 (16), 179 (85), 166 (11), 165 (16), 154 (9), 153 (44), 152 (100), 140 (14, 138 28), 126 (10), 125 (21), 124 (18, 120 (8), 112 (7), 110 (9), 99 (10), 98 (6), 97 (36), 96 (11), 86 (18), 75 (7), 73 (15), 72 (30), 71 (11), 70 (29), 69 (7), 66 (18), 65 (10), 64 (12), 60 (13), 59 (22), 58 (92), 57 (20), 54 (15), 53 (8), 52 (7), 45 (74), 44 (12), 43 (28), 42 (34), 41 (15), 39 (19), 38 (8).…”

“…26 Among the methods for the preparation of alkoxy-, 27 amino-, 28 and cyano-substituted 29 thiophenes, to the best of our knowledge, there is only one protocol leading to thiophenes, containing all of mentioned groups attached to the thiophene nucleus. 30 The proposed methodology for the synthesis of 4-alkoxy-2-aminothiophene-3-carbonitriles is based on Gewald reaction and includes a transesterification of trimethyl orthoacetate with different alcohols (3 equiv, 80 °C, 24 h) followed by Knoevenagel condensation of 'higher' orthoacetate esters with malononitrile (60 °C, 2-3 h) to give acrylonitrile intermediates, which react with sulfur in the presence of triethylamine as a base (THF, S 8 , Et 3 N, 60 °C, ca. 40 min).…”

“…The strategy consists of the following sequential short operations: (step 1) lithiation of alkoxyallene with n-BuLi in THF-hexane (5-10 min); (step 2) addition of isothiocyanate to a solution of 1-lithio-1-alkoxyallene 8 (10-20 min); (step 3) S-cyanomethylation of lithium 2-alkoxybuta-2,3-dienimidothioate 9 with 2-bromoacetonitrile followed by intramolecular cyclization of the cyanomethyl 2-alkoxybuta-2,3-dienimidothioate (1-aza-1,3,4-triene 10) thus formed to the target thiophene-2-carbonitriles 7 (15 min). Pleasingly, the overall synthesis proceeds smoothly within a short time (30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45) Scheme 2 One-pot synthesis of 4-alkoxy-5-amino-3-methylthiophene-2-carbonitriles 7 from alkoxyallenes, isothiocyanates, and 2-bromacetonitrile (via formation of new C-C bond). Reagents and conditions:…”