Quinolines tetrahydroiso

The intramolecular photoelimination of HC1 from JV-chloroacetyl derivatives of suitable amines is a useful and versatile approach to the synthesis of azaheterocycles. The iV-chloroacetyl derivative 357 has been converted in this way to 7-oxodesethylcatharanthine (358) in 55% yield.300 Investigations in this area have been particularly concerned with the A-chloroacetyl derivatives of benzylamines and phenethylamines the N-chloroacetyl-benzylamine 359 on irradiation affords the two 3-oxo-l,2,3,4-tetrahydroiso-quinolines 360 and 361.301 Competing photocyclizations have been observed in the case of l-[3-(chloroacetylamino)propyl]-3-methylindole (362) which is converted into three photoproducts, 363, 364, and 365.302... 

Substituted derivatives 219 were prepared from 1,2,3,4-tetrahydroiso-quinoline-l,4-dione 217 and sulfonyl ketene thioacetals 218. The same products were also obtained from 220 and 221 (Scheme 52) (79YZ1234). 

Enantioselective catalytic hydrogenation. The ruthenium(II) complexes of (R)- and (S)-l, bearing a chiral BINAP ligand, catalyze asymmetric hydrogenation of N-acyl-l-alkylidenetetrahydroisoquinolines to give (1R)- or (lS)-tetrahydroiso-quinolines in 95-100% ee.1 Thus the (Z)-enamide (2), prepared by acylation of 3,4-dihydropapaverine, is hydrogenated in the presence of (R)-l to (1R)-tetrahydroisoquinolines (3). The enantiomeric (lS)-3 is obtained on use of (S)-l as catalyst. 

The asymmetric alkynylation of isoquinoline iminium ion was reported in the presence of CuBr/QUINAP system (Scheme 5.7). ° Various alkynyl tetrahydroiso-quinolines were obtained in excellent yields and enantiomeric excesses. A natural product, homolaudanosine, was synthesized by the reduction of the obtained propargyl tetrahydroisoquinoline. 

Praziquantel Praziquantel, 2-(cyclcohexylcarbonyl)-l,2,3,6,7,llb-hexahydro-47f-pyrazino [2,la]isoquinolin-4-one (38.1.15), is a derivative of pyrazinoquinoline that is made in two ways [17-19], According to one of them, l-aminomethyl-l,2,3,4-tetrahydroiso-quinoline is alkylated with chloroacetic acid, and then the resulting amine is acylated with cyclohexanecarbonyl chloride to make l-(iV-carboxymethyl-iV-cyclohexylcarbonyl-aminomethyl)-l,2,3,4-tetra-hydroisoquinoline (38.1.14), which is heated at 150°C to give the desired praziquantel. 

Phenylethylamino alkaloids Simple tetrahydroiso quinoline alkaloids... 

Rommelspracher, H May, T. and Susilo, R. 1991. 3-Carbolines and tetrahydroiso-quinolines Detection and function in mammals. Planta Medica, 57 S85-S92. 

Unsymmetrical secondary and tertiary amines. Unsymmetrical amines are obtained in 50-95% yield by reaction of an alcohol and amine in the presence of this ruthenium catalyst. The intramolecular version of this reaction provides an efficient synthesis of cyclic amines either from oc,a>-amino alcohols and an alcohol or from a,tu-diols and an amine. The cyclization is useful for preparation of tetrahydroiso-quinolines.3... 

Reaction of 1 -(2-hydroxyethyl)-6,7-dimethoxy-l,2,3,4-tetrahydroiso-quinoline with 36% H2CO solution in MeOH at room temperature provided 9,10-dime thoxy-1,6,7,1 lb-tetrahyd ro-2/d,4/d-[l,3 Joxazino[4,3-flJ isoquinoline in 82% yield (09T8021). 

Another common structural component of the isoquinoline alkaloids, particularly in the protoberberines, is the 7,8-disubstituted 1,2,3,4-tetrahy-droisoquinoline unit. The spectrum of 7,8-dimethoxy-l,2,3,4-tetrahydroiso-quinoline (4) showed two interesting chemical shift changes other than the expected shifts in the aromatic carbon atoms (14). First, it was found that C-l was shielded relative to the corresponding carbon atom of 2 by —4.6 ppm. This was attributed to the y steric effect of the C-8 methoxyl group on... 

In 1964 Grewe et al.bb reported that when a mixture of isoquinoline methiodide and benzaldehyde is hydrogenated in the presence of alkali, a 64% yield of 4-benzyl-2-methyl-1,2,3,4-tetrahydroiso-quinoline can be isolated. It was postulated that reduction of isoquinoline methiodide occurs to form the 1,2-dihydroisoquinoline, which then condenses with the benzaldehyde to form 81 and this is immediately further reduced. With isoquinoline itself and a variety... 

Cyclization of 2-(2-mercaptopropanoyl)-3-methyl-l,2,3,4-tetrahydroiso-quinoline-3-carboxylic acid by treatment with ethyl chloroformate in the presence of NEt3 in CHC13 gave (3S,ll / )-cw-3,lla-H-3,llfl-dimethyl-1,3,4,6,11,1 la-hexahydro[l, 4]thiazino[4,3-6] isoquinoline-1,4-dione (86-JMC784). 

The preparation of the co-reagent of Step 1, l,3-trans-dimethyl-6,8-dibenzoyl-N-benzyl-tetrahydroisoquinoyl-5-boronic acid tetrahydroiso-quinoline, is illustrated in Eq. 2 and discussed (1). 

N-Hydroxymethylation occurs upon the catalytic decomposition of dimethoxymethane generating formaldehyde followed by Picket-Spengler cyclization forming the tetrahy-droisoquinoline. A review of the Pictet-Spengler synthesis in the preparation of tetrahydroiso-quinolines is provided (1). 

The reaction of l-phenyl-6,7-diethox -l,2,3,4-tetrahydroiso-quinoline with benzoyl C3 anide in benzene-acetic acid gave rise to 54 which on basic hydrol3 sis yielded l-phenyl-6,7-diethoxy-l,2,3,4-tetrahydroisoquinoline-1 -carboxamide. ... 

Scott JD, Williams RM. Chemistry and biology of the tetrahydroiso-quinoline antitumor antibiotics. Chem. Rev. 2002 102 1669-1730. 

Sodium (5)-prolinate-borane complex (104) reduces cyclic imine (105) to give the (S)-tetrahydroiso-quinoline derivative (106) in 87% ee. Related amines (107) and (108) are also prepared in a like manner in 86% ee and 11% ee, respectively. - ... 

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