Hydroxylated 2-(5'-salicyl)naphthalenes as protein-tyrosine kinase inhibitors

Synthesis of naphthalenes and 2-naphthols by the electrophilic cyclization of alkynes

[reactions: see text] A wide variety of substituted naphthalenes are readily prepared regioselectively under mild reaction conditions by the 6-endo-dig electrophilic cyclization of appropriate arene-containing propargylic alcohols by ICl, I2, Br2, NBS, and PhSeBr. 3-Iodo-2-naphthols have also been prepared in excellent yields by the cyclization of analogous 1-aryl-3-alkyn-2-ones. This methodology readily accommodates various functional groups and has been successfully extended to the synthesis of substituted carbazoles and dibenzothiophenes.

Synthetic studies on novel Syk inhibitors. Part 1: Synthesis and structure–activity relationships of pyrimidine-5-carboxamide derivatives

Spleen tyrosine kinase (Syk) is a non-receptor-type tyrosine kinase which mediates diverse responses in haematopoietic cells. Therefore, Syk is an attractive therapeutic target, and in a study of Syk inhibitors as potentially new therapeutic agents, we discovered the 4-anilinopyrimidine-5-carboxamides. Enzyme screening indicated that an aminoethylamino moiety at the 2-position of the pyrimidine ring was important for Syk inhibitory activity, and an investigation of the substituents at the 4-position revealed that an anilino moiety substituted at the meta position was preferred. These compounds showed high selectivity for Syk, compared to other kinases, such as ZAP-70, c-Src, and PKC, and exhibited good inhibitory activities against 5-HT release from RBL-cells. Among them, compound 9a inhibited the passive cutaneous anaphylaxis reaction in mice, with an ID50 of 13 mg/kg following subcutaneous administration. These results suggest that our compounds are worthy of further evaluation as new anti-allergic agents.

Synthesis of substituted naphthalenes and carbazoles by the palladium-catalyzed annulation of internal alkynes

An efficient synthesis of highly substituted naphthalenes has been developed by the palladium-catalyzed annulation of a variety of internal alkynes, in which two new carbon-carbon bonds are formed in a single step under relatively mild reaction conditions. This method has also been used to synthesize carbazoles, although a higher reaction temperature is necessary. The process involves arylpalladation of the alkyne, followed by intramolecular Heck olefination and double-bond isomerization. This method accommodates a variety of functional groups and affords the anticipated highly substituted naphthalenes and carbazoles in good to excellent yields.

Synthesis of substituted naphthalenes by the palladium-catalyzed annulation of internal alkynes

[reaction: see text] A variety of substituted naphthalenes have been prepared by the palladium-catalyzed carboannulation of internal alkynes. This method (1) forms two new carbon-carbon bonds in a single step, (2) accommodates a variety of functional groups, and (3) affords excellent yields of highly substituted naphthalenes.

A novel styryl diphenylamine derivative reverts the transformed phenotype of human fibrosarcoma HT1080 cells

Revertant cells, which can be isolated from transformed cells, are flat, non-transformed variants that have contributed to the elucidation of mechanisms involved in cell transformation. We have discovered that a novel styryl diphenylamine derivative converts human fibrosarcoma HT1080 cells into revertant cells. This compound induces flat cell morphology and causes a decrease in proliferative rate. The flat revertant cells not only exhibit a reduction in saturation density at confluence, but also lose the ability to proliferate in soft agar. Furthermore, their tumorigenicity is reduced when injected s.c. into athymic nude mice. The compound alters morphology in three out of seven cancer cell lines and has a potent growth inhibitory effect in six of these lines. In contrast, it has only low levels of cytotoxicity for three normal diploid cell lines. These findings indicate that this styryl diphenylamine derivative has the potential to suppress the malignant phenotype of cancer cells without profound cytotoxicity in non-transformed cells.