(cis‐6‐Methyltetrahydropyran‐2‐yl)acetic Acid, a Novel Compound from Civet (Viverra civetta)

Abstract

SummaryThe isolation and synthesis of (cis-6-methyltetrahtydropyran-2-yl)acetic acid (la), a novel compound from civet (Viverra civetta), are reported.In the course of analysis of the volatile acids of civet') we ]identified, besides various common aliphatic carboxylic acids (saturated, unsaturated, straight chain and branched, containing 2 to 18 carbon atoms), the heterocyclic carboxylic acid la2). To the best of our knowledge, neither the natural occurrence nor the synthesis of this acid has been reported.The new compound was isolated and identified in the form of its methyl ester 2a, the constitution of which was deduced from the spectral data. The mass spectrum (molecular ion at mle 172) and the NMR. spectrum (16 protons) indicated the empirical formula C9H 1603. Jnfra-red spectroscopy confirmed the presence of a non-conjugated ester group absorbing at 1740 cm-'. The 'H-NMR. spectrum revealed the nature and the relative position of the third oxygen atom with respect to the ester function. The presence of the partial structure CH3-CH-O-CH-CH2-COOCH3was suggested by signals at 6 1.14 (d, J = 6 . 5 (m, 1 H, -0-CH-CH2COO-).The methylene protons next to the ester function appeared as the A B part of an A B X system with 6,=2.40, dB=2.58, J A B = 15 Hz, J,,=6Hz, J,,=7 Hz. Irradiation at the center of this signal resulted in a simplification of the m at 3.80, and irradiation at 3.47 chan,ged the d at 1.14 3 H, CH,-CH-O-); 3.47 (m, 1 H, CH,-CH-O--); 3.69 (s, 3 H, -COOCH,);Civet is the glandular secretion from the civet cat (Viverru civetta). Together with ambergris, castoreum and musk, it is one of the few very expensive animal perfume materials [I]. l a has a very faint sour-fatty odour.

Introduction of Bicyclic Ketal Chemistry: Synthesis and Transformation Reaction of 6,8-Dioxabicyclo[3.2.1]octane Skeletal System

“…Accordingly, the two axial methine protons of the cis-isomers resonate at higher field (d = 3.10-3.35 ppm) than the corresponding protons of the trans-isomers (d = 4.01-4.12). 86 The chemical shift of H1 (d = 3.11 and 3.10 ppm) and H5 (d = 3.35 ppm) for both isomers indicates cisstereochemistry.…”

“…86 The chemical shift of H1 (d = 3.11 and 3.10 ppm) and H5 (d = 3.35 ppm) for both isomers indicates cisstereochemistry.…”

Cyclisation Reactions Involving Alkyl Enol Ethers

“…[21] This carboxylic acid is a constituent of the glandular secretion of the civet cat, which is valued in perfumery for its musky odor. [22] Excess trifluoroacetic acid (TFA) promotes the cyclisation of 11 to give the substituted tetrahydropyran 12 after addition of water with the cis-configuration between C2 and C6 (Scheme 8). Hydrolysis of the resulting secondary carbocation (or trifluoroacetate adduct) at the C4-position affords a 4hydroxy-tetrahydrofuran 12 as a mixture of diastereomers.…”

Untitled

“…The THP-ring backbone is present in many natural products of biological and pharmacological significance [5]. (+)-2-(2S,6S)-(6-Methyltetrahydro-2H-pyran-2-yl)acetic acid 1 (Figure 1) is an expensive perfume material which was isolated by Maurer and coworkers in 1978 from the perianal glandular pheromone secretion of the African civet (Viverracivetta) [6]. Civet is, together with musk, ambergris and castoreum, one of the few very expensive animal perfume materials [7].…”