Retinoidal benzoic acid derivatives

This approach has been extended substantially by the synthetic work of Dawson, Loeliger, and Frickel. Very active compounds are obtained when olefinic moieties of the classic retinoids are incorporated into a phenyl ring. Structures (19), (20), and (21) are prototypes of this novel retinoid generation and shall be referred to in general as retinoidal benzoic acid derivatives. 

X-Ray analyses of the novel retinoidal benzoic acid derivatives (20) and (21) have been carried out (Loeliger et aL, 1980 E. HMicke and F. Frickel, un-... 

Combination of the synthetic approach on which the compounds (557) and (648) are based led to retinoidal benzoic acid derivatives, for example (679) (Loeliger, 1979) and (680). For these compounds, which belong to a new generation of retinoids, Loeliger et al. (1980) proposed the name arotinoids. ... 

Hydrocarbon Ring Retinoidal Benzoic Acid Derivatives... 

A new class of aromatic retinoids that are biologically very active has been described by Loeliger et al (1980). These compounds have been called arotinoids or in a more general way retinoidal benzoic acid derivatives. One of their important features is their greatly increased chemical stability, which is a result of the aromatization of the chromophoric system. Therefore, the stability of these compounds in a labeled form should also be increased, which would greatly enhance their utility in biological experimentation. 

Several hundred retinoids have been tested in this assay, and some of the more important results are summarized in Table II. With the exception of the new retinoidal benzoic acid derivatives, few analogs have been made that are more active than either al -trans- or 13-c/.y-retinoic acid. There is little or no evidence at present that any natural known retinoid metabolite is more active in tracheal... 

Mutants of the wild type S91-C2 melanoma cells have been isolated that are resistant to the antiproliferative action of retinoic acid (Lotan et al., 1983b). The mutant cells were also resistant to growth inhibition by retinol and a retinoidal benzoic acid derivative, suggesting a single growth-inhibitory mechanism common to all of these retinoids. Uptake of the retinoids was unimpaired in the mutant cells, and the cells had normal levels of CRABP. These results contrast with those of the retinoid-resistant embryonal carcinoma cell line mutants that were deficient in CRABP (Schindler et al., 1981). Eventually a mechanism of action of the retinoids will have to be described that can explain these diverse results, and mutants such as these should prove invaluable to such studies. 

Similarly, retinyl acetate suppressed the ability of cultured keratinocytes, derived from a human squamous cell carcinoma, to form cross-linked envelopes at the cell periphery (Rice et al., 1983). Cell envelope protein production was inhibited also by the retinoidal benzoic acid derivative TTNPB ethyl ester (G6) (Stadler et a/., 1983). 

Topical isotretinoin, 0.2% in a vanishing cream base and applied twice daily for 20 weeks, led to decreased lesion counts, no cutaneous irritation, and a 30% decrease in skin surface lipids in 20 patients with acne (Plewig et al., 1983). Topical administration of the retinoidal benzoic acid derivative TTNPB ethyl ester (G6) was toxic to hamsters in concentrations of 0.(X)l-0.3% causing dermatitis, hair loss, bone deformation, and fracture. Concentrations of 0.(XX)1% and lower were nontoxic. This suggests that topical applications of this agent in man may not be of clinical use because of the observed toxicity. 

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