1 methyl tetrahydroisoquinoline

Enzymatic Resolution of 1-Methyl-tetrahydroisoquinoline using Candida rugosa Lipase... 

Deracemizations of chiral secondary amines employing the variant MAO-N D3 in combination with ammonia borane complex (a) 1-methyl-tetrahydroisoquinoline (20 mM) (b) 2-phenylpyrrolidine (100 mM). 

Some further examples of stereoselective deprotonation/alkylation reactions of tricarbonyl-chromium complexed (V-methyl tetrahydroisoquinolines have been reported27. Starting with the enantiomerically pure (35)-methyl tetrahydroisoquinoline reaction with hexacarbonyl-chromium led to a mixture of endo- (40%) and exo- (60%) complexes, which were deprotonated with butyllithium and subsequently methylated with iodomethane. In this way methylation occurred firstly at the 4- and secondly at the 1-position. In all cases, the methyl group entered anti to the chromium complexed face. After separation of the alkylated complexes by chromatography and oxidative decomplexation, the enantiomerically pure diastereomers (—)-(l 5,35,47 )-and ( + )-(17 ,35,45)-1,2,3,4-tetrahydro-l,2,3,4-tetramethylisoquinolme were obtained, benzylic amines such as tetrahydroisoquinoline to 2-amino-4,5-dihydrooxazoles. Deprotona... 

In the case of acetophenone reactants l-aryl-l-methyl-tetrahydroisoquinolines are obtained. Conditions a mixture of 5 mmol of the b-phenylelhylamine derivative, 5 mmol of the aldehyde/ketone and 0.8 g E4a in ethanol was heated at 80 °C for 20/40 h. The solid was filtered off, the filtrate was evaporated and the residue characterised. Yields, according to NMR, are from 75-100 %. The catalyst could be easily recycled without significant loss of activity. 

Makino, Y., Ohta, S., Tachikawa, O. and Hirobe, M. (1988) Presence of tetrahydroisoquinoline and l-methyl-tetrahydroisoquinoline in foods compounds related to Parkinson s disease. Life Sci. 43 373-378. 

Reactions of 3- and 4-piperidone-derived enamines with a dienester gave intermediates which could be dehydrogenated to tetrahydroquinolines and tetrahydroisoquinolines (678). The methyl vinyl ketone annelation of pyrrolines was extended to an erythrinan synthesis (679). Perhydrophenan-threnones were obtained from 1-acetylcyclohexene and pyrrolidinocyclo-hexene (680) or alternatively from Birch reduction and cyclization of a 2-pyridyl ethyl ketone intermediate, which was formed by alkylation of an enamine with a 2-vinylpyridine (681). 

The rhodium(II) acetate catalyzed reaction of 2-(3-oxo-2-diazobutyryl)-1,2,3,4-tetrahydroisoquinoline in boiling toluene yielded 2-methyl-4,6,7,l 16-tetra-hydro[l, 3]oxazino[2,3-n]-isoquinoline-4-one in 72% yield (99TL8269). 

After all the compounds which were cited in the older literature as diaziridines had been shown to be incorrectly formulated, the first authentic diaziridines appeared in the literature in 1959. Schmitz obtained A-methyl-1,2-diaziridino-l, 2,3,4-tetrahydroisoquinoline (34)... 

Reactions of 3-methyl-1,2,3,4-tetrahydroisoquinoline-1-acetamides 202 (R = H) with 36% aqueous CH2O at 60 °C gave 1,3,4,6,7,1 Ih-hexahydro-2//-pyrimido[6,l-a]isoquinolin-2-ones 152 and their 3-methyl derivatives (97LA1165). When the reaction was carried out in the presence of 37% aqueous NaOH 3-hydroxymethyl derivatives 151 were obtained. Reactions with PhCHO were stereospecific to afford only diastereomers 203. 

Treatment of (11 aS)-3-isopropyl-11 a-methyl-4-phenyl-1,6,11,11 a-tetrahy-dro[l,4]oxazino[4,3-6]isoquinolin-l-one (243) with 6N HCl in a pressure tube, then the reaction of the work-up residue with propylene oxide gave (3S)-3-methyl-l,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (244) (99S704). 

The thermal condensetion of p-benzyloxyphenylacetic acid and of 3-methoxy-4-hydroxy-phenethylamine occurs and gives, with a yield of 86% to 92%, the N-(3-methoxy4-hydroxy-phenethyl-p-benzyloxyphenylacetamide from this latter, by cyclization according to Bischler-Napieralski with phosphorus oxychloride in acetonitrile, followed by reduction with sodium borohydride, there is obtained with a yield of 75% to 80% the 1-(p-benzyloxybenzyl)-6-meth-oxy-7-hydroxy-1,2,3,4-tetrahydroisoquinoline, which is methylated with formaldehyde and formic acid giving 1 (p-benzyloxybenzyl)-2-methyl-6-methoxy-7-hydroxy-1,2,3,4-tetrahydro-isoquinoline with a yieid of 90%. 

Carbet hoxy methyl-6,7-dimethoxy-1, 3,4-tetrahydroisoquinoline Tetrabenazine... 

A route for the asymmetric synthesis of benzo[3]quinolizidine derivative 273 was planned, having as the key step a Dieckman cyclization of a tetrahydroisoquinoline bis-methyl ester derivative 272, prepared from (.S )-phcnylalaninc in a multistep sequence. This cyclization was achieved by treatment of 272 with lithium diisopropylamide (LDA) as a base, and was followed by hydrolysis and decarboxylation to 273 (Scheme 58). Racemization could not be completely suppressed, even though many different reaction conditions were explored <1999JPI3623>. 

Stereostructures of a co-crystal of (li )-l- 4-[(9aA)-perhydropyrido[l,2- ]pyrazin-2-yl]phenyl -2-phenyl-7-hydroxy-l, 2,3,4-tetrahydroisoquinoline with ERa-LBD301-553/C — S triple mutant <2005JME364> and iV-[2-(4-hydroxyphenyl)ethyl]-a-propyl-3-[(4-hydroxyphenyl)methyl]-l,4-dioxo-l,2,3,4,ll,l la-hexahydro-67/-pyrazino[l,2- ]isoquinoline-3-acetamide with fructose-1,6-biphosphatase <2003JBC51176> were determined by X-ray crystallography. The structure of a complex formed from 3-[( -methylphenyl)amino]-4-[(4-methylphenyl)imino]-4//-pyrido[l,2-tf]pyrazine with sodium bis(trimethylsilyl)amide and (norbornadiene)Mo(CO)4 in THF was characterized by single crystal X-ray diffraction <1995JPR38>. 

The subject of metabolism of tetrahydroisoquinolines and related alkaloids in mammalian metabolic systems has recently been reviewed (205, 206). The formation of biogenic amine-derived alkaloids in mammals and their transformation by O-methylation reactions have been described. 

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