Cholest-8(14)-enol is the major radioactive component of the 4-di-demethyl sterol fraction biosynthesized from 4,4-dimethyl[2-(3)H(2)]cholest-8(14)-enol by rat liver microsomal fractions, and therefore the first steps in the biosynthesis of cholesterol from the latter compound probably involve removal of the 4-methyl groups. 4,4-Dimethylcholesta-8,14-dienol therefore is not an intermediate in t...

Computations provide insight to the stability and isomeric possibilities of thiotropocin, tropodithietic acid, and troposulfenin. Thiotropocin and tropodithietic acid contain a flat 7-membered ring and delocalized pi-bonds similar to those of tropylium ion (C(7)H(7)(+)). Troposulfenin is far less stable; it contains a puckered tropone ring and localized bonds similar to 1,3,5-cycloheptatriene. ...

A novel salicylideneaniline type fluorescent organogelator based on a 3,4,5-(tri-dodecyloxy)benzoyl group immobilizes aromatic solvents. The resulting gels show enhancement in emission and thermochromic/non-photochromic behaviour during sol-to-gel transition.

The enol of a-cyano-a-phenylacetic acid was observed as a short-lived transient species formed upon flash photolytic generation of phenylcyanoketene by a photo-Wolff reaction of a-cyano-a-diazoacetophenone followed by hydration of the ketene. Rates of ketonization of the enol were measured in dilute hydrochloric acid solutions and acetic acid, biphosphate ion, tris(hydroxymethyl)methylamine, an...

A robust method for preparing (E)and (Z)-stereodefined fully substituted enol tosylates is described. α-Substituted β-keto esters undergo (E)-selective enol tosylations using TsCl–Me2N(CH2)6NMe2 as the reagent (method A, 13 examples; 63–96%) and (Z)-selective enol tosylations using TsCl–TMEDA–LiCl as the reagent (method B, 13 examples; 62–99%). A plausible mechanism for the (E)and (Z)-enol tosy...

quirement that 13 be converted to an enol, which is also a methylenecyclobutane totally shuts down turnover. That 13 is not a better inhibitor reveals the subtlety of the recognition of this enzyme for its substrate. The isoleucine precursor cu,p-dihydroxy-p-methylvaleric acid differs from 13 only by the addition of two hydrogens. The activity of vinyl fluoride 15, possibly acting as a stable e...

Highly colored (red) solutions of various enol silyl ethers and tetranitromethane (TNM) are readily bleached to afford good yields of alpha-nitro ketones in the dark at room temperature or below. Spectral analysis show the red colors to be associated with the intermolecular 1:1 electron donor-acceptor (EDA) complexes between the enol silyl ether and TNM. The formation of similar vividly colored...