C/s-Crotonates

Synonyms Ciodrin Ciovap Cyodrin Cypona E.C. 3-((Dimethoxyphosphinyl)oxy)-2-butenoic acid 1-phenylethyl ester (9,(9-Dimethyl (9-(l-methyl-2-carboxy-a-phenyl-ethyl)vinyl phosphate Decrotox Dimethyl-c/.s-l-methyl-2-(l-phenylethoxycarbo-nyl)vinyl phosphate Dimethyl phosphate of a-methylbenzyl 3-hydroxy-c/.s-crotonate Duo-kill Duravos ENT 24717 l-Methylbenzyl-3-(dimethoxyphosphinyloxo)isocroto-nate a-Methylbenzyl-3-(dimethoxyphosphinyloxy)-c/ -crotonate a-Methylbenzyl 3-hydroxycrotonate dimethyl phosphate Pantozol 1 c/.s-2-(l-Phenylethoxy)carbonyl-l-methylvinyl dimethyl phosphate SD 4294 Shell SD 4294 Volfazol. 

The reaction of 3-chloro-3-(2-thienyl)-3//-diazirine with alkyl-substituted alkenes gave predominantly the trans-isomer of 5 while with acrylates, crotonates and styrene, the c/s-isomer predominated. The reaction of chloro(2-thienyl)carbene with (Z)- and ( )-but-2-ene proceeded with the retention of alkene stereochemistry. 

Capillary GLC analysis (12 m, cross-linked methyl silicone, programmed, 45°C, S C/mln, retention time of ethyl (Z)-crotonate, 2.5 min). Ethyl (E)-crotonate has a retention time of 2.95 min under the same conditions. Careful quantitative analysis reveals that the ratio of Z and E isomers is reproducibly in the range 58 1 to 59 1. 

Synonyms Apavinphos 2-Butenoic acid 3-((dimethoxyphosphinyl)oxy)methyl ester 2-Carbomethoxy-l-methylvinyl dimethyl phosphate a-Carbomethoxy-l-methylvinyl dimethyl phosphate 2-Carbomethoxy-l-propen-2-yl dimethyl phosphate CMDP Compound 2046 3-((Dimethoxyphosphinyl)oxy)-2-butenoic acid methyl ester 0,0-Dimethyl-0-(2-carbomethoxy-1 -methylvinyl)phosphate Dimethyl-1 -carbomethoxy-1 -propen-2-yl phosphate (9,0-Dimethyl 1-carbomethoxy-l-propen-2-yl phosphate Dimethyl 2-methox-ycarbonyl-l-methylvinyl phosphate Dimethyl methoxycarbonylpropenyl phosphate Dimethyl (l-methoxycarboxypropen-2-yl)phosphate 0,0-Dimethyl 0-(l-methyl-2-carbox-yvinyl)phosphate Dimethyl phosphate of methyl-3-hydroxy-c/5 -crotonate Duraphos ENT 22324 Fosdrin Gesfid Gestid 3-Hydroxycrotonic acid methyl ester dimethyl phosphate Meniphos Menite 2-Methoxycarbonyl-l-methylvinyl dimethyl phosphate c/5 -2-Methoxycarbonyl-l-methylvinyl dimethyl phosphate l-Methoxycarbonyl-l-propen-2-yl dimethyl phosphate Methyl 3-(dimethoxyphosphinyloxy)crotonate NA 2783 OS 2046 PD 5 Phosdrin c/.s-Phosdrin Phosfene Phosphoric acid (l-methoxycarboxypropen-2-yl) dimethyl ester. 

The conversion experience is found in Ingold s response to a paper presented by Robinson at the Chemical Society in the summer of 1925 and sent to Ingold before its publication in 1926. Robinson s paper, written with J. Allen, A. E. Oxford, and John C. Smith, classified conjugated systems into nine categories of reactants, two of them "anionoid" and the rest "cationoid." "Crotonoid" and "crotenoid" were two of the nine types. This was a detailed and cumbersome classification, based on studies of crotonic acid, amino acids, and their salts, in which crotenoid was an instance of anionoid (electron donor) reaction and crotonoid of cationoid (or electron acceptor) reaction. 

Ferreira, D. et al.. Circular dichroic properties of flavan-3,4-diols, J. Nat. Prod., 67, 174, 2004. Cai, Y. et al.. Biological and chemical investigation of dragon s blood from croton species of South America. Part 1. Polyphenolic compounds from Croton lechleri. Phytochemistry, 30, 2033, 1991. Cui, C.B., Davallin, a new tetrameric proanthocyanidin from the rhizomes of Davallia mariesii Moore, Chem. Pharm. Bull, 39, 2179, 1991. 

The reaction is carried out in vapour phase (250°C) using a flow system (see methods section). This procedure turned out to be essential in order to mantain the hydrogen transfer as the main reaction pathway. A batch experiment carried out in an autoclave actually showed a wide range of condensation products besides some saturated ketone [6]. Reactions of ketones over oxide catalysts can lead to a variety of products due inter alia to aldol condensation, intramolecular dehydration and intermolecular disproportionation [16]. However, the presence of a good hydrogen donor such as a secondary alcohol and vapour phase conditions favour the transfer hydrogenation as the major reaction [16,17]. In our reaction conditions, products attributable to crotonic condensations and subsequent 1,4 Michael addition [18] were observed by g.l.c.-m.s. (Table 1). 

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