The Preparation of Chloromethyl Vinyl Ketones

Abstract

The structural assignment is based upon composition, infrared and nuclear magnetic resonance spectra.The infrared spectrum (carbon tetrachloride) of II had a band at 11.08 µ which is characteristic of the 6/3,-19-oxido bridge.1 The n.m.r. spectrum8 of the oxide lacked the C-19 methyl signal of starting t-steroid and was further characterized by the C-19 methylene multiplet centered at 6.23 r,9 Jab = 12 c.p.s., 5ab, 0.13 p.p.m. (2H); the unresolved C-6 multiplet at 6.68 r (1H); and the cyclopropyl C-4 methylene centered at 9.75 (2H).Treatment of 3a,5a-cycIo-6/3,19-oxidocholestane (II) with a trace of sulfuric acid in aqueous acetone for two hours yielded A5-choIestene-3/3,19-diol (II) in 80% yield. The identity of this material was proved by comparison with a known sample (melting point, mixture melting point, infrared) prepared by the method of Bowers.1 Experimental10 3a, 5a-Cyclo-6/3,19-oxidocholestane (II).-Lead tetraacetate 4.68 g. (0.107 mole) was recrystallized from benzene and dried in vacuo for 3 hr. It was dissolved in 250 ml. of dry benzene and 50 g. (0.5 mole) of anhydrous calcium carbonate was added.(5) M.

Synthesis of Substituted 1‐Thiocyanatobutadienes and Their Application in a Diels—Alder/[3,3] Sigmatropic Rearrangement Tandem Reaction.

“…According to the procedure described by Hudson et al [22], we started our synthesis from the highly toxic, commercially available 1,3-dichloroacetone 12. According to the literature procedure the intermediate salt formed from the S N 2 reaction between the dichloroketone and triphenylphosphine was isolated in 85% yield.…”

“…The mixture was allowed to stand for 30 min and the white precipitate was dried in air to provide a white powder of pure 13 (67.58 g, 191.6 mmol, 97%). Ylide 13 has been described by Hudson et al [22]. Mp 179-180 C (Ref.…”

Synthesis of 6‐substituted pyrimidines by the wittig reaction. II . Via 2‐acetamido‐4‐hydroxy‐5‐phenylbutylpyrimidine‐6‐carboxaldehyde

“…For example, Hudson and Chopard (4) studied the condensation of a variety of aldehydes with chloroacetonyl triphenyl phosphorane (III); the yields varied from about 30-48% with high ratios of weakly electrophilic aldehydes such a s benzaldehyde, butyraldehyde and furfuraldehyde. In contrast, the strongly electrophilic p-nitrobenzaldehyde in only 25% excess gave a 79% yield of Wittig product (4,5). They rationalized (4) that the poor yields were due to instability; although it i s true that these compounds a r e sensitive, the highly unsaturated chloromethyl ketones, I V znd V which could be expected to be even more sensitive w e r e obtained in 64 and 62% yields, respectively by condensation of p-nitrocinnamaldehyde (I) o r 5-@-nitrophenyl)-2,4-pentadiene-l-al (11) with the chloracetonyl phosphorane (111) (5).…”

“…They rationalized (4) that the poor yields were due to instability; although it i s true that these compounds a r e sensitive, the highly unsaturated chloromethyl ketones, I V znd V which could be expected to be even more sensitive w e r e obtained in 64 and 62% yields, respectively by condensation of p-nitrocinnamaldehyde (I) o r 5-@-nitrophenyl)-2,4-pentadiene-l-al (11) with the chloracetonyl phosphorane (111) (5). Thus, it was noted that p-nitrobenzaldehyde in slight excess (4,5) and the nitroaldehydes, I and I1 (5) in equivalent amounts to III could be condensed in good yield, but that less electrophilic aldehydes required a 5-10 fold excess to proceed in even poor yield (4).…”

Reaktionen CH‐aktiver Verbindungen mit Aziden, XXX. Synthese von (Diazomethyl)phosphoniumsalzen durch Diazogruppen‐Übertragung

“…Einem komplexen Produktgemisch begegnet man bei der entsprechenden Reaktion von 1Oc -f mit 2 in Methylenchlorid. Zwar entstehen auch hier noch die a-Diazophosphoniumsalze 12c -f (19-61%) -die Teils als Tetraphenylborate isoliert werden, neben 13 (XO = Bre; 19-34%) -doch entfallen wesentliche Reaktionsanteile auf die Bildung der 2-Acyliminobenzthiazoline 6 (R wie 12c -f)s) sowie von (Brommethy1)triphenylphosphonium-tetrafluoroborat (14).…”