100646-39-7Relevant academic research and scientific papers
Retinobenzoic acids. 3. Structure-activity relationships of retinoidal azobenzene-4-carboxylic acids and stilbene-4-carboxylic acids
Kagechika,Himi,Namikawa,Kawachi,Hashimoto,Shudo
, p. 1098 - 1108 (2007/10/02)
Alkyl-substituted azobenzene-4-carboxylic acids are potent differentiation inducers of human promyelocytic leukemia cell line HL-60 to mature granulocytes. Their structure-activity relationships are very similar to those of other retinoidal benzoic acids which are generally represented by 4 and named retinobenzoic acids. The structure-activity relationships of azobenzenecarboxylic acids can also be applied to the known retinoid TTNPB (3). Thus, (E)-4-[2-(3,4-diisopropylphenyl)-1-propenyl]benzoic acid (St30 (28)), and (E)-4-[2-(3-tert-butylphenyl)ethenyl]benzoic acid (St40) (29)), the acyclic alkyl analogues of TTNPB, are nearly as active as retinoic acid. Among the oxidatively derived compounds (Az90, Ep series and Ox series) of azobenzene- or stilbenecarboxylic acids, Az90 (71) and Ep80 (61) have strong activities. However, all the bishydroxylated derivatives of TTNPB are inactive, while a diketo analogue Ox580 (69) has only weak potency. The activities of conformationally restricted compounds of TTNPB offer some information on the stereochemistry of the active form of these retinoidal compounds.
The ion-pair mechanism and bimolecular displacement at saturated carbon. VI. Razemization and radio-bromide exchange for substituted 1-phenylbromoethanes; solvent effects
Stein, Allan R.
, p. 363 - 371 (2007/10/02)
Racemization and radio-bromide exchange kinetics for 1-phenylbromoethanes in acetonitrile and in nitromethane using tetrabutylammonium bromide are reported.The results, together with those previously reported for acetone solutions, provide direct empirical support for the ion-pair mechanism for nucleophilic substitution at saturated carbon.Changing the substituents on the phenyl from the 4-nitro through to the 3,4-dimethyl substrate and the solvent from acetone to the more polar acetonitrile and nitromethane shifts the transition state for bromide substitution from an early to a late stage of the equilibria series substrate intimate ion pair various solvated ion pairs free or dissociated ions.For all the substrates in acetone and, for the species giving the less stable carbocations, in acetonitrile and nitromethane, both racemizations and exchanges are bimolecular.In the latter solvents, the substrates giving the more stable carbocations show mixed kinetics.
Preparation of chiral 1-phenylethanols and bromides
Stein, Allan R.,Dawe, Robert D.,Sweet, James R.
, p. 3442 - 3448 (2007/10/02)
A fast, convenient procedure for preparing and resolving moderate to large quantities of chiral secondary alcohols is described.The general procedure involves a one-pot conversion of the ketone (various acetophenones) to the half-ester of a diacid (succinic, phthalic...) and resolution with (+)- and (-)-1-phenylethylamines.Overall yields of the enantiomeric alcohols, the variously substituted 1-phenylethanols, are generally 65-85percent with optical purities of approximately 90percent.Properties and optical rotations of a number of chiral 1-phenylethanols and of the bromides made from them are tabulated.A discussion of optical purity determinations using nmr methods is included and absolute configurations are reported.
Process for the preparation of substituted vinylbenzyl chloride
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, (2008/06/13)
An improved continous single step vapor phase process for the preparation of substituted vinylbenzyl chloride from substituted ethyltoluene is disclosed. In this process a substituted ethyltoluene is reacted with a halogen gas in the vapor phase, at elevated temperatures via a continuous feed process. Furthermore, this process achieves halogenation followed by dehydrohalogenation in a single pass through the reactor. There is also obtained a very high total selectivity to vinylbenzyl chloride and its precursors via this continuous process.
