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7-substituted tricyclic

When electron-withdrawing groups are introduced at the vinyl moiety, ary-lethenes may behave as dienophiles. Thus a-trifluoromethyl styrene (111) interacted with Danishefsky s diene (12b) under thermal or high pressure conditions [37] to regioselectively afford a 1 1 mixture of cycloadducts which were then converted to 4-phenyl-4-trifluoromethyl-2-cyclohexen-l-one (112) (Equation 5.12). A direct access to angularly trifluoromethyl-substituted tricyclic compounds may be achieved by cycloaddition of the l-trifluoromethyl-3,4-di-hydronaphthalene (113) with diene 12b (Equation 5.13). [Pg.223]

Similarly, condensation of 206 with carbon disulfide under basic conditions gives rise to the mercapto-substituted tricyclic system 207 in good yield (Equation 55) <2000AF904>. This approach has also been used for related systems of substituted pyrimidines <1999JHC1119, 2000PS( 163) 1 >. Hydrazine-substituted pyrimidines have also been reacted in an analogous manner <1998JRM1248>. [Pg.736]

The aryl iodide 22 undergoes a Pd-catalysed cross-coupling with C-, N- and O-nucleophiles to yield the substituted tricyclic chromans 23 with good diastereoselectivity (Scheme 8) <99JOC1875>. [Pg.321]

Photolysis of fully substituted tricyclic Dewar pyridines carrying 2,3,4-triObutyl) substituents (7) produces azaprismanes (8), which, on standing or further irradiation, give the pyridine derivatives (9) (89T3115). [Pg.480]

Reactions of 5f/-2-methyl-l,2,4-triazepino[2,3- ]benzimidazol-4-one 71, prepared by reaction of 1,2-diaminobenz-imidazole 72 with acetoacetic ester 73, with different reagents was described, in the search of new heterocycles with biological activity <2002CHE598>. When lactam 71 was treated with aromatic aldehydes in boiling 1-BuOH with addition of piperidine 74, 577-3-arylidene-2-methyl-l,2,4-triazepino[2,3- ]benzimidazol-4-ones 75a-c were obtained (Scheme 7). Coupling lactam 71 with phenyldiazonium chloride 76 in dioxane afforded the 3-phenylazo-substituted tricycle 77. When 71 was treated with phosphorus pentasulfide 78 in boiling dioxane or pyridine, its thio analog 79 was obtained. The reaction proceeded most efficiently when lactam 71 was refluxed with twofold excess of 78 in dry dioxane. These thiones 79 react with ammonia and amines by nucleophilic substitution. When 79 was refluxed with ammonia, benzylamine, piperidine, or morpholine, the 4-amino-substituted tricycles 80a-d were obtained. All the described compounds were identified by NMR, mass spectrometry, and IR spectroscopy. [Pg.409]

Charette recently described an innovative activation protocol in which lactams, in the presence of triflic anhydride (33), react with pyridines to afford the pyridinium imidate 107 in good yield. Subsequent addition of metal enolates to this species leads to 2-substituted tricyclic dihydropyridines, advanced intermediates for the total synthesis of the natural alkaloid ( )-tetraponerine T4 (109, Scheme 16) [107]. [Pg.139]

Table 1 lists the experimental conditions for the electrochemical formation of a cyclopropyl ring from a variety of 1,3-dihaloalkanes, mostly from dibromoalkyl derivatives. A free cyclopropyl ring as well as a spiro derivative (entry 6), bicyclobutanes (entries 8-10) and other fused and highly strained systems such as tricyclene (entry 11) and a propellane derivative (entries 12,13) were obtained. In addition, Carroll and Peters have found evidence for the intermediacy of [2.2.1 ]propellane upon reducing 1,4-dihalonorbor-nanes electrochemically at a low temperature, although attempts to isolate it were unsuccessful. The intramolecular electrochemical reduction of a dihalo-substituted tricyclic compound leads to cyclization with formation of a tetracyclic derivative in which... [Pg.917]

The imidoyl cholorides 252 and the 2-aminobenzhydrol 253 gave the amidines 254, which were cyclized to the phenyl-substituted tricycles 255 by heating in concentrated hydrochloric acid. ... [Pg.333]

The aforementioned route has been used to prepare the 4-substituted tricyclic trioxanes (135), and (136) from the -2-(methoxymethylidene)cyclohexanones (239) and (240), and (139) from the Z-methoxymethylidene derivative (241) (Scheme 31) <92JA8328, 92JMC2459,94JMC1256, 95JMC2273>. In all these cases, only the endo methoxy epimers are reported. No mention is made of equilibration... [Pg.887]

An additional heterocyclic ring fused to a (6 5 6) system can be constructed by a cyclocondensation reaction of an appropriately substituted tricyclic derivative with an external reagent. The NH2-CN functionality of (177) was transformed into a pyrimidine by the reaction with formamide <91H(32)895>, and cyclocondensation of the Ac-OH functionality in (178) with phenyl-hydrazine gave a pyrazole <9lH(32)90l>. A hydrazino derivative (179) was condensed with a carboxylic acid to give a 1,2,4-triazole in the reaction that involves an N-2 atom of (179) <88Ci(L)785>. [Pg.1082]

Retrosynthetic analysis leads a new strategy in the synthesis of the ABC core using a Bradsher cycloaddition [83]. Cleavage of the resulting oxazolidinone ( Scheme 22) and a subsequent series of reactions gave a suitably substituted tricyclic core, which can be used in the synthesis of the pentacyclic skeleton ABCDE. [Pg.631]

Keyes, R.F., Carter, J.J., Zhang, X. and Ma, Z. (2005) Short and efficient synthesis of a vinyl-substituted tricyclic erythromycin derivative. Organic Letters, 7, 847-849. [Pg.269]

Selenium-substituted tricyclic siloxanes such as 149 react via free-radical mechanisms with Bu"3SnH/AIBN to give a variety of products (AIBN = 2,2 -azobisisobutyronitrile) <2000JA1343, 1997JOC5676>. [Pg.944]

Rearrangement by thermolysis of unsymmetrically substituted tricyclic derivatives of 2,6-epi-dioxypiperidine (118) afforded the ketamide (119) (Equation (17)) <90KGS109>. Synthesis of N-substituted 5-azalactanone (121) was accomplished by CO insertion. Thexylborane-cyanidation hydroboration protocol proved to be the most useful method with moderate to high yield (Equation (18)) <82JOC1494>. [Pg.422]

Zinc Derivatives Oxazoles and benzoxazoles can be lithiated in the 2-position by alkyllithium. In transmetallation of lithiated oxazole excess zinc dichloride gave the highest yield. The zincated substrates 106 and 107 were used in Negishi-type coupling (Scheme 45). Reactions of zincated oxazoles and benzoxazole with aryl halides all proceed well. A similar reaction sequence was used in the preparation of a 2-oxazolyl-substituted tricyclic structure 108. [Pg.441]

Two reports have been pnbhshed by Naimi-Jamal et al. and Singh et al., making nse of 2-naphthol for the construction of variably substituted tricyclic 4//-pyrans 39 (Schemes 13.13 and 13.14, respectively) [21, 22]. Naimi-Jamal et al. used 10mol% of sodium carbonate under solvent-free conditions at high temperatures to afford the desired products 39 in excellent yields (88%-quant.) (Scheme 13.13). [Pg.422]

Cyclotriphosphazene containing alkynes react with a cobalt cyclopenta-dienyl complex. The cobalt facilitates both 2 + 2 and 2 + 2 + 2 cycloadditions, Scheme 31. When indene is added, it takes part in the 2 + 2 + 2 variant in creating a substituted tricyclic phosphazene. The 2+2 cyclobutane product is formed when indene does not take part in the reaction. This reaction favors the tricycle over the cyclobutane by an approximate 2 to 1 ratio. [Pg.335]

The organocatalysed formal 3 + 3-cycloaddition reaction of acrolein and 2,3-disubstituted indoles formed highly substituted tricyclic hydrocarbazoles in good to excellent yields (up to 99%) and excellent enantioselectivities (99% ee) ... [Pg.509]

Novel 4-phenylsulfanyl substituted tricyclic indeno[2,1-d]pyrimidines as tyrosine kinase inhibitors and antiangiogenic agents... [Pg.83]

Silver(i)-catalysed isomerization of the substituted tricyclic hydrocarbons (533) takes place with methyl migration. Compound (534 R = Me) was synthesized independently. The stereochemistry of (534 R = Ph) was deduced by the effect of lanthanide n.m.r. chemical shift reagents on the epoxide obtained from (534 R = Ph). [Pg.150]


See other pages where 7-substituted tricyclic is mentioned: [Pg.730]    [Pg.737]    [Pg.210]    [Pg.83]    [Pg.183]    [Pg.210]    [Pg.712]    [Pg.135]    [Pg.322]    [Pg.11]    [Pg.116]    [Pg.322]    [Pg.360]    [Pg.506]    [Pg.542]    [Pg.109]    [Pg.172]    [Pg.388]    [Pg.8]    [Pg.291]    [Pg.95]    [Pg.409]    [Pg.83]    [Pg.313]    [Pg.341]    [Pg.156]    [Pg.434]    [Pg.155]   
See also in sourсe #XX -- [ Pg.207 ]




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