Isoquinoline synthesis

Benzimidazo[2,1 -a]isoquinolines synthesis, 5, 161 Benzimidazole, 1-acetyl-reactions... 

Pyrazolo[3,4-d][l,2]diazepines synthesis, 7, 597 Pyrazolop, 4- 6][ 1,4]diazepines synthesis, 5, 272 Pyrazolo[l, 4]diazepinones as anticonvulsant, 1, 170 Pyrazolo[2,3-e]diazepinones synthesis, 5, 272 1 H-Pyrazolo[l,5-6]imidazoles synthesis, 6, 992 Pyrazolo[2,3-a]imidazoles biological activity, 6, 1024 Pyrazolo[2,3-c]imidazoles reactions, 6, 1041 synthesis, 6, 1047 Pyrazolo[2,3-imidazoles synthesis, 6, 991 Pyrazolo[3,2- njisoquinolines synthesis, 5, 339 Pyrazolop, 4-c]isoquinolines synthesis, 5, 273 Pyrazolonaphthyri dines synthesis, 5, 339 Pyrazolone, diazophotolysis, 5, 252 Pyrazolone, 4,4-dihalo-rearrangements, 5, 250 Pyrazolone, ethoxy-hydrazinolysis, 5, 253 Pyrazolone, 4-halo-... 

Pyridazino[4,5 -c]isoquinoIine, 6-aryI-synthesis, 3, 244 Pyridazino[3,4-c]isoquinoIines alkylation, 3, 238 JV-oxide, 3, 327 synthesis, 3, 247-248 Pyridazino[4,3-c]isoquinolines synthesis, 3, 247 Pyridazino[4,5-c]isoquinolines alkylation, 3, 238 Pyridazin-3(2H)-one, 6-acryIoxy-polymers, 1, 288... 

BISCHLER NAPIERALSKI Isoquinoline synthesis Isoqutnoline synthesis Irom amides of phenethylamines... 

PICTET SPENGLER Isoquinollne Synthesis Isoquinoline synthesis ol phenethylammes and pyruvic acid derivatives... 

The Pictet-Spengler reaction has been carried out on various solid support materials " and with microwave irradiation activation.Diverse structural analogues of (-)-Saframycin A have been prepared by carrying out the Pictet-Spengler isoquinoline synthesis on substrates attached to a polystyrene support. Amine 20 was condensed with aldehyde 21 followed by cyclization to give predominantly the cis isomer tetrahydroisoquinoline 22 which was further elaborated to (-)-Saframycin A analogues. 

The Bischler-Napieralski reaction is one of the traditional methods for isoquinoline synthesis, and has been applied to the preparation of fused quinolizidine systems. One simple example is the transformation of compound 246 into a 9 1 mixture of diastereomers 247 and 248 by treatment with phosphorus oxychloride followed by sodium borohydride reduction of a nonisolated iminium salt resulting from the cyclization (Scheme 49) <2000BMC2113>. 

Holsworth, D. D. Pictet—Gams Isoquinoline Synthesis In Name Reactions in Heterocyclic Chemistry, Li, J. J. Corey, E. J., Eds. Wiley Sons Hohoken, NJ, 2005, 457—465. (Review). 

Isoquinoline synthesis via acid-mediated cyclization of the appropriate ami-noacetal intermediate. 

Using the tandem aza-Wittig/bir-electrocyclization strategy, an isoquinoline synthesis starts with salicylaldehyde, which is converted with azido-... 

Reticuline (38), one of the most important intermediates in the biosynthesis of opium alkaloids, has been synthesized in racemic form (Scheme 7) (78). 6-Methoxy-7-benzyloxyisoquinoline (39), prepared from O-benzylisovanillin via a modified Pomeranz-Fritsch isoquinoline synthesis, was treated with benzoyl chloride and potassium cyanide to obtain Reissert compound 40. Alkylation of the anion generated from 40 with 3-benzyloxy-4-methoxybenzyl chloride gave the corresponding 1-substituted Reissert compound 41 which was hydrolyzed in alkaline medium to 1-benzylisoquinoline derivative 42. Quatemarization of 42 with methyl iodide followed by sodium borohydride reduction and debenzylation led to ( )-reticuline (38) in about 25% overall yield from 39. 

Isoquinoline synthesis Bischler-Napieralski synthesis is used to synthesize isoquinolines. (3-phenylethylamine is acylated, and then cyclodehy-drated using phosphoryl chloride, phosphorus pentoxide or other Lewis acids to yield dihydroisoquinoline, which can be aromatized by dehydrogenation with palladium, for example in the synthesis of papaverine, a pharmacologically active isoquinoline alkaloid. 

The first synthesis of a derivative of 2,8-phenanthroline was reported by Merz, Weidlich, and Fink13 in 1964. They prepared 5,6-dimethoxy-2,8-phenanthroline (34) (isolated as the dipicrate) in very low yield by conducting a double Pomeranz-Fritsch isoquinoline synthesis on 4,5-dimethoxyisophthalaldehyde. The parent compound was prepared 2 years later12 in 25-35% yield, along with 1,9-phenanthroline (4%), by the photocyclization of trans-1 (3-pyridyl)-2-(4-pyridyl)ethylene in benzene. This reaction was used by Hiinig and his colleagues15 to prepare an N,N -dimethyl diquaternary salt of 2,8-phenanthroline by methylating the crude product from the irradiation reaction. 

Phenanthroline was first claimed to have been synthesized by a double Pomeranz-Fritsch isoquinoline synthesis.11 It has recently been prepared12 in about 12% yield by the irradiation of trans-l,2-di(3-pyridyl)ethylene in benzene, along with 1,8-phenanthroline (12-20%) and 1,10-phenanthroline (1-2%). The melting point is quite different from that recorded earlier by Ruggli and Schetty.11 This latter method has subsequently been used15 to prepare an AT, AT -dimethyl diquaternary salt of 3,8-phenanthroline by methylating the crude product from the irradiation reaction. 

An attempt to utilize this conversion of amines into aldehydes in an isoquinoline synthesis was not successful.439 Instead, reaction between 2-(3,4-dimethoxyphenyl)ethylamine and isatin afforded only the spiro compound 150.439 Reaction between isatin and 2-(3-hydroxy-4-methoxyphenyl)ethylamine gave a mixture of two spiro compounds, while a reaction of isatin, this amine, and benzylamine gave 6-hydroxy-7-methoxy-l-phenyl-1,2,3,4-tetrahydroisoquinoline.439... 

Isocyanophosphonates, aldol reactions, 227 Isoquinoline synthesis, enamide reactions, 33 Isomerization allylic amines, 9, 95 olefins, 118, 171 see also specific compounds Isopulegol, 102 Isotactic polymers, 174 chloral, 182 photoirradiation, 347 methacrylates, 181 propylene, 174 Isotacticity, 177... 

Isoquinoline Synthesis. Olefins that contain certain neutral donor functionalities are also effectively hydrogenated. Investigation of the enan-tioselective hydrogenation of enamide substrates has resulted in a general procedure for the asymmetric synthesis of isoquinoline alkaloids. 

---