4-Styrylthiazoles. Syntheses and Relationships Among Ultraviolet Absorption Spectra

Abstract

the type I (1). These halo ketones have been found to react with thioamides and related compounds, apparently without complication due to the conjugated unsaturation, to yield the 4-styrylthiazoles (II). The latter compounds may be regarded as analogs of stilbene derivatives. Stilbene derivatives and such stilbene analogs as styryl derivatives of pyridine, benzoquinoline, benzothiazole, and acridine have been studied as growth inhibitors and carcinogenic agents (2); the styrylthiazoles described here may be of interest in the same connection. Numerous 2-styrylthiazoles are known, but 4or 5-styrylthiazoles, in which the carbon to carbon double bond of the thiazole ring is conjugated directly with the styryl group, have apparently not been reported previously. A report of the preparation of 5-styrylthiazole (3) was later found to be in error (4).The ultraviolet absorption spectra of these compounds, most of which show two or more strong bands, afford an opportunity to compare effects produced by a variety of substituent groups (phenyl, methyl, amino, hydroxyl, mercapto) with effects due to corresponding groups in derivatives of aromatic hydrocarbons. It has been found that spectral effects in this 4-styrylthiazole series can often be predicted remarkably well from relationships which have been found to hold among derivatives of quite a different family of compounds, the polynuclear aromatic hydrocarbons, which have been chosen for comparison here

Synthesis of (E)-Stilbenes and (E,E)-1,4-Diphenylbuta-1,3-diene Promoted by Boron Trifluoride-Diethyl Ether Complex

“…The reaction between 4-phenylbutan-2-one (1d) and benzaldehyde (2a) and between 1-phenylpropan-2-one (1a) and aliphatic aldehyde 2l (propanal) or 2m (citral) did not provide the desired alkenes ( Table 1, entries 17-19), whereas the reaction between 1-phenylpropan-2-one (1a) and cinnamaldehyde (2i) proceeded smoothly (entry 9); this indicates that benzylic hydrogens adjacent to the ketone (1a, 1b, 1c) and an aldehyde functionality directly attached to an aromatic ring (2a-h, 2j, 2k) or conjugated with an aromatic ring (2i) are essential to form the (E)-stilbenes (3a-h, 3j, 3k) or (E)-1,4-diphenylbuta-1,3-diene (3i). It is noteworthy to mention here that under basic conditions (KOH) the reaction between 1-phenylpropan-2one (1a) and benzaldehyde (2a) resulted in the synthesis of 1,4-diphenylbut-3-en-2-one in our own studies, as described by Southwick and co-workers 31 (Scheme 1).…”

Synthesis, Evaluation, and Comparative Molecular Field Analysis of 1-Phenyl-3-amino-1,2,3,4-tetrahydronaphthalenes as Ligands for Histamine H1 Receptors

“…Column chromatography with CH 2Cl2:methanol (9:1) afforded 77 mg (50%) of a light brown oil. This was dissolved in ethereal HCl, and the salt recrystallized from ethanol to afford 15 mg (16%) of colorless crystals: mp 211-212 °C; 1 wick et al 29 in 72% yield as a crude brown oil (21 g) estimated as 60% pure by gas chromatography, and used unpurified in next synthetic step.…”

Synthesis and Pharmacological Evaluation of 3-(3,4-Dichlorophenyl)-1-indanamine Derivatives as Nonselective Ligands for Biogenic Amine Transporters

“…1-(3,4-Dichlorophenyl)-3-(3-methoxylphenyl)-1-propen-3-one (2). By use of a previously described procedure, , 2 was prepared 11 in 93% yield as a colorless solid from 3,4-dichlorobenzaldehyde and 3-methoxyacetophenone: mp 116 °C; 1 H NMR δ 7.74−7.14 (m, 8H), 3.89 (s, 3H).…”