Patent GB-971913-A (GB)
Title: Process for the production of substituted azulenes
IPC: C07C1/32
Filed: 1961-03-14
Abstract: Substituted azulenes are produced by reacting a 1- or 3-alpha-aminoalkyl, -hydroxyalkyl or -alkoxyalkyl azulene with a complex acid, or condensing a 1- and/or 3-unsubstituted azulene with a carbonyl compound (or reactive derivative thereof) in presence of a complex acid, isolating the resulting 1- or 3-alkylidene azulenium salt and reacting it with a compound having a reactive hydrogen atom or its metal salt or with an organometallic compound or a metal hydride. In examples 7-9, 11 and 12, compounds of formula <FORM:0971913/C1/1> wherein X is -CH(CO2Et)2, -N(CH3)2, morpholino, -OCH3 or -OH, are produced by reacting 1-ethylidene-4, 6, 8-trimethyl azulenium fluoborate or perchlorate with sodiomalonic ester, dimethylamine, morpholine, sodium methoxide and sodium hydroxide, respectively. In Example 10, the compound <FORM:0971913/C1/2> was obtained by reacting 3-benzylidene guaiazulenium fluoborate with piperidine. In Example 13, 1-ethoxymethylene 4, 6, 8-trimethyl azulenium fluoborate was obtained from 4, 6, 8-trimethylazulene, fluoboric acid and ethyl orthoformate and reacted with sodium hydroxide to give the aldehyde (first formula above, XCH3 in side chain replaced by =0).  Specification 858,839 is referred to.ALSO:Substituted azulenes are produced by reacting a 1- or 3-alpha-aminoalkyl, -hydroxyalkyl or -alkoxyalkyl azulene with a complex acid, or condensing a 1- and/or 3-unsubstituted azulene with a carbonyl compound (or reactive derivative thereof) in presence of a complex acid, isolating the resulting 1- or 3-alkylidene azulenium salt and reacting it with a compound having a reactive hydrogen atom or its metal salt or with an organometallic compound or a metal hydride. In examples: (1) 1-benzylidene-4, 6, 8-trimethyl azulenium fluoborate (1st formula), prepared from 4,6,8-trimethylazulene, fluoboric acid and benzaldehyde, was reacted with LiAlH4 to give 1-benzyl-4,6,8-trimethylazulene (2nd formula); (2) 1-ethylene-4,6,8-trimethylazulenium fluoborate, from trimethylazulene, fluoboric acid and <FORM:0971913/C4-C5/1> acetaldehyde, was reacted with LiAlH4 to give 1-ethyl-4,6,8-trimethylazulene; (3) the product of the first example was reacted with benzaldehyde and fluoboric acid giving 3-benzylidene-1-benzyl - 4,6,8 - trimethylazulenium fluoborate which with LiAlH4 gave 1,3-dibenzyl-4,6,8-tri-methylazulene; (4) 1 - alpha - hydroxybenzyl-4,6,8-trimethylazulene gave with perchloric acid 1 - benzylidene - 4,6,8 - trimethylazulenium perchlorate which with phenyl magnesium bromide afforded 1 - (diphenylmethyl) - 4,6,8 - trimethylazulene; (5) 1-isopropylidene azulenium fluoborate, from azulene, acetone and fluoboric acid reacted with methyl magnesium iodide giving 1-t-butylazulene; (6) 1-ethylidene-4,6,8 - trimethylazulenium fluoborate reacted with methyl lithium giving 1-isopropyl 4,6,8-trimethylazulene; (10) 3-benzylidene guaiazulenium fluoborate of formula <FORM:0971913/C4-C5/2> is prepared from guaiazulene, benzaldehyde and fluoboric acid; (11) 1-ethylidene-4,6,8-trimethyl azulenium perchlorate is prepared from 1-a -hydroxyethyl - 4,6, - trimethyl azulene, acetic anhydride and perchloric acid.  Specification 858,839 is referred to.