Debenzylation of 2,6,8,12-tetraacetyl-4,10-dibenzyl-2,4,6,8,10,12-hexaazatetracyclo[5.5.0.03,11.05,9]dodecane

The debenzylation of 2,6,8,12-tetraacetyl-4,10-dibenzyl-2,4,6,8,10,12-hexaazatetra-cyclo[5.5.0.0^3,11.0^5,9]dodecane by catalytic hydrogenolysis in a mixture of HCOOH with other RCOOH (R = Me, Et, Prⁱ) is accompanied by the N-formylation of the liberated secondary amino groups. The alkaline hydrolysis of the obtained products makes it possible to remove the formyl groups with the retention of the acetyl groups.     

Molecular structure of methyl 20-isopropyl-15(E)-hydroxyimino-5,9-dimethyl-18-oxahexacyclo [12.4.0.22,13.118,20.05,10.04,13]heneicosane-9-carboxylate

Methyl 20-isopropyl-15(E)-hydroxyimino-5,9-dimethyl-18-oxahexacyclo[12.4.0.2^2,13.1^18,20.0^5,10.0^4,13]-heneicosane-9-carboxylate is synthesized and its molecular structure is determined. Compound IIa of C₂₇H₄₁NO₄ crystallizes in the acentric P2₁ space group with the following unit cell parameters: a = 7.6511(7) ?,b = 12.0698(11) ?, c = 12.9182(12) ?, β = 95.257(2)°.     

1,4,7,10-tetraazatetracyclo[5.5.1.04,13.010,13]tridecane: Degenerate rearrangement of its conjugate acid

The highly symmetrical 1,4,7,10-tetraazatetracyclo[5.5.1.0^4,13.0^10,13]tridecane (1) has been synthesized by two methods. The proton NMR spectrum of 1 is analyzed. The cyclic tetraaminomethane derivative undergoes a remarkable series of degenerate prototropic and conformational equilibria. The temperature dependence of the proton NMR spectra of 1 and its conjugate acid 3 are interpreted in terms of a large rate enhancement of intramolecular nucleophilic addition to guanidinium ion 3 (ring-chain tautomerism) compared to its acyclic counterpart.     

Molecular structure of methyl-10,14,19,19-tetramethyl-4-oxo-20-oxahexacyclo [15.3.1.16.18.06.15.09.14017.21]docosane-10-carboxylate

The synthesis of methyl-10,14,19,19-tetramethyl-4-oxo-20-oxahexacyclo[15.3.1.1^6.18.0^6.15.0^9.140^17.21] docosane-10-carboxylate III is performed and its molecular structure is determined. Compound III C₂₇H₄₀O₄ crystallizes in the monoclinic system with the cell parameters as follows: a = 12.8081(11) ?, b = 7.0384(6) ?, c = 12.8904(12) ?, β = 105.828(2)^o, P2₁ space group, Z = 2, d = 1.273 mg/m³.     

Molecular and crystal structure of 23,24,25,26,27,29,30-heptamethyl-19,28-oxahexacyclo[15.13.18.017,18.013,14.08,9.05,10]tetracos-3-yl acetate

The molecular structure of 23,24,25,26,27,29,30-heptamethyl-19,28-oxahexacyclo[15.13.18.0^17,18.0^13,14.0^8,9.0^5,10]tetracos-3-yl acetate III. Compound III C₃₂H₅₂O₃ crystallizes in the monoclinic crystal system with the unit cell parameters a = 13.265(15) ?, b = 6.481(7) ?, c = 32.274(4) ?, β = 99.333(2)°, space group C2, Z = 4, d = 1.176 g/cm³. Original Russian Text Copyright ? 2009 by N. I. Medvedeva, O. B. Flechter, and A. A. Korlyukov __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 50, No. 2, pp. 399–401, March–April, 2009.     

A photoelectron spectroscopic study of proximity effects in 8,11-disubstituted pentacyclo(5.4.0.02.6 .03,10 .05,9) Undecanes

Photoelectron spectra of six 8,11-disubstituted pentacycloundecanes (1, 3 - 7) are reported; the results suggest that the through-space interaction betweeen unsaturation centers in 1 and 3 dominates over the through-bond interaction mechanism.     

Molecular structure of 8-carboxy-18-chloro-14-hydroxy-20-isopropyl-16-methoxy-4,8-dimethyl-15-oxaoctacyclo-[11.7.1.03,1204,9012,19014,18016,21017,20]henicosane

The structure of 8-carboxy-18-chloro-14-hydroxy-20-isopropyl-16-methoxy-4,8-dimethyl-15-oxaoctacyclo[11.7.1.0^3,120^4,90^12,190^14,180^16,210^17,20]henicosane has been determined by single crystal X-ray diffraction. Original Russian Text Copyright ? 2008 by R. R. Fazlyev, G. F. Vafina, and F. Z. Galin __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 49, No. 6, pp. 1179–1181, November–December, 2008.