Spiro isoquinolines

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... 

Reductive JV(2)-cycloalkylation of 1,3,4,6,7,llfc-hexahydro-2H-pyra-zino[l,2-a]isoquinolin-4-one with 4-spiro derivatives of cyclohexanone in... 

Chemical Name (+-)-[Hydroxy-6-methoxy-5-methyl-llH-cyclopenta[i,j]-isoquinoline]-7-spiro-l -(2,5-cyclohexadiene-4-one)... 

Stevens rearrangement of methoiodides of 2,3,4,6,ll,lla-hexahydro-l//-pyrazino[l,2-h]isoquinolin-l-ones in the presence of 0.5 eq LAH gave T-methylindane-2-spiro-2 -piperazin-3 -ones (73CPB2661). When 10 eq LAH were applied, the oxo group of the spiro derivatives was also reduced [74GEP2356999,74JAP(K)74/72276]. 

A new synthetic route to the phthalide-isoquinoline and spiro-benzyl-isoquinoline alkaloids has been developed. The indeno[2,l-a]benzazepine (105),... 

Reactions of the easily obtainable spirocyclopropenes 10 with aza-hetero-cycles or azines such as pyridines, pyridazines, quinolines, isoquinolines, azaphe-nanthrenes, and others afford spiro (1,8a) dihydroindolizine 7 in good yields (50-84%) (Scheme 3). The intermediate in this synthesis is the colored betaine 9. Typical dihydroindolizines have been made via this route.1 7 16-18... 

A three-component one-pot synthesis of highly substituted spiro[l,3]oxazino[2,3-a]isoquinolines has been demonstrated <03TL729>. The starting materials are quinoline, DMAD, and either 1,2- or 1,4-quinones. An example is shown. 

Syntheses and biological properties of isoquinolines spiro-fused at the 4-position with carbo- and heterocycles 02KGS1475. 

Preparation of 2 ,3 -dihydro-6 ,7 -methylenedioxy-2 -trifluoroacetyl-spiro[cyclo-hexa-2,5-dien-4-one-l,4 -(lH)isoquinoline]-3 -carhoxylic acid methylamide 194 [125] Polymer-supported diacetoxyiodobenzene 185 (5.82 g, 7.5 mmol, 1.1 mmol g 1.5 equiv.) was added portionwise over 10 min to a solution of... 

A, few isochroman-3-ones occurs in nature The importance of isochroman-3-ones however is because they are valuable intermediates for the synthesis of isoquinolines. A most interesting use of isochroman-3-ones is that they provide benzocyclobutenes which are valuable synthons for berbines, spiro-benzylisoquinolines, 3-aryl isoquinoline, benzophenanthridines, benzocarbazoles, yohimbin, tetracycline, steroids etc. 

The complex spiro hetero-/-fused naphtho[l,2-6]pyrans e.g. 63 show two absorption bands (444 - 474 and 568 - 582 nm) and have half-lives of 2 - 3 minutes <00JP344761, 00JP344762>. The synthesis of 4-acetoxy-l-phenyl-2-naphthylamine from 4-hydroxy-l-phenylnaphthalene-3-carboxylic acid allows annulation of an isoquinoline unit onto 1-naphthol and subsequent reaction with a propynol yields the fused pyranophenanthridine 64, Xmax 550 nm, t /2= 12 s (polymethacrylate) <02USP6379591>,... 

Benzo[a]quinolizidin-2-ones can be degraded in certain acidic media to 3,4-dihydroisoquinolines <83JOC1075>. For example, treatment of 2-iminobenzo[a]quinohzidines (146) with thioglycolic acid under a variety of experimental conditions led to the thiazolo[2,3-a]isoquinoline (149) instead of the expected spiro compound (148), and the same result was obtained starting from ketone (147) (Scheme 20) <90H(3l)2065>. These results were explained according to the mechanism, which is a... 

Oxazoles.—Formation. ci)-Diazoacetophenone reacts with benzonitrile in the presence of trifluoromethanesulphonic acid to give 2,5-diphenyloxazole (514). Bi-, ter-, and quater-oxazoles have been synthesized from a-metallated isocyanides thus lithiobenzyl isocyanide (PhCHLiNC) and dimethyl oxazole-3,4-dicarboxylate afford compound (515). Stable methylene-oxazolines (516 R = Me or Ph) are obtained by heating the iminesHN=C(Ph)OCHRC=CH. The fluorinated oxazoline (518) results from the action of benzonitrile on the oxiran (517), and also from the reaction of bis(trifluoromethyl)carbene with the benzoylimine (CF3)2C=NCOPh/ Treatment of 2-acylamino-l-aryl-alkan-l-ols (519) under the conditions of the Pictet-Gams reaction, i.e. with phosphorus pentoxide in boiling toluene or xylene, results in cis- and trans-2-oxazolines (520), rather than isoquinolines, as claimed previously. The spiro-oxazolines (521 R = Me or Ph) are formed when the lithiated di-isocyanide CN—CH2CH2CHLi—NC is treated with acetone or benzophenone, respec-tively. ... 

---