CD 271 possesses a potent anti- inflammatory activity in a large number of models particularly when compared with known reference anti-inflammatory agents. Retinoids (all-trans retinoic acid, 13 cis retinoic acid and Etretinate) show very weak or no activity.

The retinoic acid receptors (RARs) transduce retinoid dependant gene regulation, and many biological effects of retinoids are mediated through binding and activation of three closely related receptor subtypes (RAR alpha, RAR beta, and RAR gamma). In order to investigate the role of receptor subtypes, we have carried out a chemical synthesis program to seek selective retinoids for these receptors. We measured receptor binding affinity using recombinant RAR alpha, -beta, and -gamma proteins and assessed cellular differentiating activity in F9 murine teratocarcinoma cells (F9 cells). This research has identified the 4-substituted-3-(1-adamantyl)phenyl moiety as a new pharmacophore which can replace the beta-cyclogeranylidene ring of the naturally occurring all-trans-retinoic acid. Two chemical series derived from the general structures 6-(3-tertioalkylphenyl)-2-naphthoic acid (series I) and 4-[(E)-2-(3-tertioalkylphenyl)propenyl]benzoic acid (series II) were developed. In particular, we have obtained the RAR gamma selective derivatives 6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthoic acid (7) [Ki(RAR alpha) = 6500 nM, Ki(RAR beta) = 2480 nM, Ki(RAR gamma) = 77 nM] and 4-[(E)-2-[3-(1-adamantyl)-4-hydroxyphenyl]propenyl]benzoic acid (19) [Ki(RAR alpha) = 1,144 nM, Ki(RAR beta) = 1245 nM, Ki(RAR gamma) = 53 nM]. In series I, the presence of a phenol group, irrespective of the nature of tertioalkyl group, imparted at least partial RAR gamma selectivity, whereas in series II, the presence of both adamantyl and phenol groups is needed to confer RAR gamma selectivity. The RAR gamma selective ligands induce differentiation in F9 cells (7, AC50 = 33 nM; 19, AC50 = 66 nM). From series I, a mixed RAR beta-gamma agonist with potent cellular differentiating activity was selected for development as a topical antiacne agent, 6-[3-(1-adamantyl)-4-methoxyphenyl]-2-naphthoic acid (5, CD 271) [Ki(RAR alpha) = 1100 nM, Ki-(RAR beta) = 34 nM, Ki(RAR gamma) = 130 nM, AC50(F9) = 37 nM]. Finally, from series II, we have obtained a weak antagonist in the F9 cellular differentiation assay, 4-[(E)-2-(3-tert-butyl-4-hydroxyphenyl)propenyl]benzoic acid (15, IC50 = 700 nM).

Using cultured human keratinocytes, three bioassays for retinoic acid-like substances have been developed. They are based on the ability of these substances (1) to inhibit cross-linked envelope formation, (2) to inhibit the synthesis of the Kl keratin, and (3) to stimulate the synthesis of the K19 keratin. The data, expressed as 50% inhibitory or activating concentrations were used to rank compounds according to their activity.

A convenient three step synthetic route starting from readily available materials was used for the synthesis of novel 5-(2-tetrahydroanthracenyl)-2-furan and -2-thiophenecarboxylic acid derivatives. The main features of the sequence are a Heck reaction between a substituted styrene derivative and bromo heterocycles, followed by high yield electrophilic cyclisation/aromatization of the intermediate thus obtained to afford the desired compounds.

Retinoic acid and some selected analogs were tested to evaluate their effect on skin morphogenesis and toxicity in the chick embryo. Retinoids dissolved in dimethyl sulfoxide were injected at doses varying from 10 pmol to 10 mumol into the amniotic cavity of 10-day-old chick embryos (n = 20). At 16 days of incubation, the eggs were opened to record the number of dead embryos and the number of embryos presenting club-shaped feathers. A lethal embryotoxic dose (LED50d16) which, at 16 days of incubation, provokes the death of 50% of the embryos and an effective dose (ED50) which induces production of club-shaped feathers in 50% of surviving embryos were then calculated using log-probit analysis. Retinoids could be classified according to their ED50. For example, arotinoid Ro 13-7410 appears approximately 1,000 times more active than all transretinoic acid. However, the analogs which are more active are also more toxic. The assay described in the present study appears to be a simple and useful model for the screening of retinoids.

A high through-put method to assay for binding of retinoids to their cytosolic binding protein is described. The protein-bound retinoid is quantified following its complete separation from the free ligand by a single gel filtration chromatography step on Sephadex G-25 columns. The method allows a single person to process up to 100 samples per day. A new, substituted benzo[b]thiophene carboxylic acid derivative (tritiated) is proposed as an alternative ligand for cytosolic retinoic acid binding protein. This new analog (CD270), which contains no olefinic double bonds, is characterized by its chemical stability to light and atmospheric oxidation. This molecule shows binding characteristics similar to those of retinoic acid, both in terms of binding affinity and binding specificity (Kd of about 2 nm), and offers the additional advantage that the unbound molecule is absorbed on Sephadex G-25, while the protein-bound ligand is unaffected by the carbohydrate gel matrix. When the affinities of retinoic acid and several analogs were determined by competition binding experiments, similar results were obtained when either tritiated retinoic acid or tritiated CD270 were used as the labeled ligand. The tritiated, heterocyclic retinoic acid analog, CD270, is thus proposed as an alternative ligand for cytosolic retinoic acid binding protein.

7-hydroxy-TTNN, a possible metabolite of the aromatic retinoid: 6-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)-2-naphthoic acid (TTNN) (2), was synthesized through a short route, the key step of which was a one pot oxidation/cyclisation/aromatisation of a 1,5 diol to afford the phenolic ring C (see scheme 1).

Evidence is presented that retinoids have topical and systemic antiinflammatory actionsin vivo. This degree of antiinflammatory activity, as assessed in different model systems is often similar to that observed for standard reference antiinflammatory agents of both the non steroidal or corticosteroidal type.

In mouse skin, antiproliferative agents including retinoids inhibit induction of ornithine decarboxylase activity by a variety of hyperproliferative stimuli. In the hairless rat skin, ornithine decarboxylase activity was induced by ten successive strippings with cellotape and by topical application of 12-O-tetradecanoyl-phorbol-13-acetate. Topical application of all trans-retinoic acid (25 nmol/cm2) immediately after the tape stripping of the skin significantly inhibited the induction of ornithine decarboxylase activity at all time points measured. The inhibition by all trans-retinoic acid of ornithine decarboxylase induced by cellotape stripping was dose dependent as was found to be the case for arotinoid, retinol, Ro-10-1670, motretinid, 13-cis-retinoic acid, etretinate, and vitamin A. Oral administration of all trans-retinoic acid also inhibited the ornithine decarboxylase activity induced by cellotape stripping. We propose the assay of ornithine decarboxylase activity in the hairless rat epidermis after tape stripping for a rapid evaluation of new retinoids.

A benzonaphthalene compound has the formula (I) wherein R1 represents (i) or (ii) -CH2OH; R6 represents or OR7 wherein R7 represents hydrogen, alkyl having 1-20 carbon atoms, monohydroxyalkyl or polyhydroxyalkyl, r' or r'' represent hydrogen, lower alkyl, mono or polyhydroxyalkyl, aryl or a residue of an amino acid or a sugar, or together form a heterocycle; R2 represents hydrogen, alkyl having 1-15 carbon atoms, alkoxy having 1-4 carbon atoms or a cycloaliphatic radical; R3 represents hydrogen, hydroxy, alkyl having 1-4 carbon atoms, alkoxy having 1-10 carbon atoms, a cycloaliphatic radical, a thiocycloaliphatic radical or -O-Si(CH3)2-R8 wherein R8 represents lower alkyl; and R4 and R5 represent hydrogen, lower alkyl, hydroxy or lower acyloxy. This compound is useful in the topical and systemic treatment of dermatologic diseases and in the treatment of the degeneration of conjuctive tissues. The compound also possesses anti-tumor activity.

Abstract1,8‐dihydroxy‐[10‐14C]9‐anthrone (anthralin) was synthesized in good yield starting from readily available 3‐methoxy‐2‐(2‐methoxybenzyl)‐benzoic acid (3).14C was introduced via carboxylation of the Grignard derived from 3‐bromo‐2(2‐methoxybenzyl) anisole. This, in turn, was obtained from (3) by a Curtius and Sandmeyer reaction sequence.

The interaction between anthralin and DNA in vitro was examined. According to our data, there is no evidence for a specific interaction between these substances. However, we found that the addition of small quantities of DNA or albumin significantly enhanced the stability of aqueous solutions of anthralin and markedly affected the rate of anthralin decomposition.