Patent GB-701911-A (GB)
Title: Improvements in or relating to new compounds having an ambergris scent and their preparation process
IPC: C07C45/60
Filed: 1950-10-26
Abstract: The invention comprises (1) compounds of the formula <FORM:0701911/IV (b)/1> where R11 is -CH2-CH2-, -CH2-CH2-CH2- or -CH2-CH=CH-; and (2) a mixture containing at least two of the isomers represented by the formulae <FORM:0701911/IV (b)/2> <FORM:0701911/IV (b)/3> <FORM:0701911/IV (b)/4> where R1 is -CH2OH or -CHO.  A typical mixture of alcohols has a B.P. of 116-7 DEG  C. at 0.01 mm. and yields a 3 : 5-dinitrobenzoate of M.P. 133-5 DEG  C.  A similar mixture of aldehydes has a B.P. of 100-5 DEG  C. at 0.01 mm., d420 of 0.993-5 and nD20 of 1.512-4, and gives a semicarbazone of M.P. 223-5 DEG  C.  The compounds are made from a 2 : 5 : 5 : 9-tetramethyl-decalin having halogen hydroxy or acetoxy in the 2-position and one of the following in the 1-position: -CH2CH2OH, -CH2CHO, -CH2CH2CH2OH or -CH2 CH2CHO, by splitting off the 2-substituent together with a hydrogen atom from an adjacent carbon atom or from the hydroxy group in the 1-position (aldehyde reacting in its enolic form).  The reaction may be effected by distillation under reduced pressure or by heating with a dehydration catalyst such as copper bronze or alumina (at 200-300 DEG  C.).  The starting materials which contain 16 carbon atoms are obtained from the ozonlysis of sclareol oxide (degradation product of sclareol from oil of sage), which yields inter alia 2-acetoxy-2 : 5 : 5 : 9-tetramethyl - decalyl-ethanel and the corresponding aldehyde and acid.  The acid may be reduced to the alcohol directly or via the ester obtained by alcoholysis of the 2-acetoxy group (e.g. with methanolic sulphuric acid; lactone is intermediate).  Reduction of acid, ester or aldehyde to alcohol may be effected before, after or simultaneously with elimination of the 2-substituent; thus the saturated ester yields the unsaturated ester on heating with iodine or methanolic sulphuric acid.  The starting materials with 17 carbon atoms are obtained from ambrein (scentless constituent of ambergris) either by ozonolysis and reduction or by oxidation to ambreinolide and reduction; ambrienolide may also be obtained from sclareol oxide or manool or by cyclization of farnesylacetic acid.  In the examples, (1) the neutral fraction from the ozonolysis of sclareol oxide is distilled under reduced pressure over copper bronze or sebacic acid and fractionated to give a mixture of aldehydes of the above formulae (R1=-CHO); alternatively the crude ozonolysis product is so treated and the acidic fraction subsequently removed; (2) the acidic fraction from the ozonolysis of sclareol oxide (or the product of permanganate oxidation of the neutral fraction) is heated in vacuo with copper bronze and the resulting unsaturated acid reduced with lithium aluminium hydride to give a mixture of alcohols of the above formula (R1 = -CH2OH); (3) the starting material of (2) is heated with methanolic sulphuric acid and the resulting 2-hydroxy-2 : 5 : 5 : 9-tetramethyldecalyl-1-acetic acid methyl ester dehydrated by heating with iodine; the resulting unsaturated ester is reduced with lithium aluminium hydride to the same product as (2); if sufficient sulphuric acid is used the iodine treatment is unnecessary; (4) the first step of (3) is carried out in two stages by treatment of the material with alcoholic potash to give a lactone and alcoholysis of the latter with methanolic sulphuric acid; (5) the lactone of (4) is reduced with lithium aluminium hydride or with sodium and alcohol to 2-hydroxy - 2 : 5 : 5 : 9 - tetramethyldecalyl - 1 - ethanol; vacuum distillation over alumina then yields the product of (2); (6) the lactone of (4) is treated with ethanolic hydrogen chloride to give 2-chloro-2 : 5 : 5 : 9-tetramethyldecalyl-1-acetic acid ethyl ester; vacuum distillation yields an unsaturated ester which is reduced to the product of (2) by the Bouveault method or by lithium aluminium hydride; (7) the glycol of (5) is heated with naphthalene-2-sulphonic acid and fractionally distilled under reduced pressure to give the epoxide of the above formula (R11 = -CH2-CH2-); (8) as in (7) using alumina for dehydration; an unsaturated alcohol is also obtained: (9) ambrein ozonide is catalytically reduced to 2-hydroxy-2 : 5 : 5 : 9-tetramethyldecalyl-1-propionaldehyde which is treated as in (8) to yield the epoxide of the above formula (R11 = -CH2-CH = CH-) which may be catalytically reduced to the epoxide (R11 = -CH2-CH2-CH2-); (10) sclareol oxide is ozonized and the ozonide reduced with lithium aluminium hydride; the product which is a mixture of the glycol of (5) and the epoxide of (7) may be treated as in (7) or (8); (11) 2-hydroxy-2 : 5 : 5 : 9-tetramethyldecalyl-1-propanol (from lithium aluminium hydride reduction of ambreinolide) is heated with methanolic sulphuric acid to give the epoxide (R11= -CH2-CH2-CH2-) and the mixture of alcohols (R1= -CH2-CH2-OH); the latter (3 : 5-dinitrobenzoate described) is oxidized by chromic acid to the aldehyde (R1= -CH2-CHO; semicarbazone described); (12) the glycol of (5) is treated with ethereal hydrogen chloride, giving (a) the epoxide (R11= -CH2-CH2-); (b) 2-chloro-2 : 5 : 5 : 9-tetramethyldecalyl-1-ethanol; (c) the product of (2); and (d) an unsaturated chloride; heating the mixture in vacuo converts (b) into (a) and (c), (a) being a stereoisomer of the product of (7) and (8); distilling the mixture followed by hydrolysis with caustic potash gives a mixture of (a) and (c) which can be separated by chromatography on alumina.ALSO:Perfumes are made from ambergris-scented compounds of the formula <FORM:0701911/VI/1> where R11 is -CH2-CH2-,-CH2-CH2-CH2- or -CH2-CH = CH- or a mixture of at least two of the isomers represented by the formulae <FORM:0701911/VI/2> where R1 is -CH2-OH- or CHO; mixtures of these may be used.  A typical composition contains a mixture of alcohols (R1 = CH2OH), the epoxide (R11 = -CH2-CH2-), a -and b - amyrins anod g -dihydroionone.