Azaspiro- -decane system

The reaction of propane-1,3-diamine with phthalic anhydride gives the pyrimidoisoindolone (415), some of whose reactions were investigated Syntheses of the l,8-diazaspiro[4,5]decane (416) and l-oxa-8-azaspiro-decane (417) systems have been reported. ... 

Pinna muricata has also yielded the two original acids pinnaic add and tauropinnaic add, which have the same 6-azaspiro-[4,5]-decane system. These two derivatives... 

Scheme XXXVI. Cyclization leading to an azaspiro-[4.5]-decane system rather than the desired azaspiro-[5.5]-undecane (259). A i) SOCb, pyridine, ii) NaNHi, NH3. B i) Dihydropyran, ii) n-ButylLi, methyl chloroformate, iii) Toluenesulphonic acid, iv) Lindlar s Pd, H2, v) CrOa, vi) Oxalyl chloride. C i) Cul, hexamethylphosphoric triamide, ethyl 4-lithiobutylacetaldehyde acetal. D i) HCl, ii) CH3SO2CI, (C2H5)3N, iii) LiBr, iv) NaN02. E i) Zn, NH4CI. F i) Heat...

Alkaloids Containing an Azaspiro[4.5]decane Ring System Halichlorine... 

Initial addition reaction of methyloxirane to 4-methyl-l-oxa-4-azaspiro[4.5]decane 164 is followed by ring expansion under thermal conditions. O-Nucleophilic attack is directed on quaternary carbon of the spiro system rather than on C-4 carbon of the oxazolidine ring, and 8,10-dimethyl-7,13-dioxa-10-azaspiro[5.7]tridecane 165 is a major product of the transformation (Scheme 42 <1995IZV1838>). 

The isolation in the last decade of natural products incorporating the 1-azaspiro[4.5]decane ring system that have been shown to display... 

The connective Pummerer sequence has been applied to the preparation of the 2-azaspiro[4.5]decane motif present in a number of important biologically active conpounds and natural products IFigure 20.31. The construction of this system is consequendy significant in the synthesis of new active analogues. Even where other methods are available, Pummerer routes offer new opportunities for the assembly of structurally varied congeners. 

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