Spiro , crystal structure

The novel highly substituted spiro[4.4]nonatrienes 98 and 99 are produced by a [3+2+2+2] cocyclization with participation of three alkyne molecules and the (2 -dimethylamino-2 -trimethylsilyl)ethenylcarbene complex 96 (Scheme 20). This transformation is the first one ever observed involving threefold insertion of an alkyne and was first reported in 1999 by de Meijere et al. [81]. The structure of the product was eventually determined by X-ray crystal structure analysis of the quaternary ammonium iodide prepared from the regioisomer 98 (Ar=Ph) with methyl iodide. Interestingly, these formal [3+2+2+2] cycloaddition products are formed only from terminal arylacetylenes. In a control experiment with the complex 96 13C-labeled at the carbene carbon, the 13C label was found only at the spiro carbon atom of the products 98 and 99 [42]. 

Closer inspection of the blocks in the crystal structure, however, reveals some interesting variation as far as the individual spatial arrangements are concerned. The most compact association is found in the 1 2 inclusion compound of the spiro host 22 with dimethylformamide48> (Fig. 23, type la). This aggregate preserves a perfect twofold (C2) molecular symmetry in the crystal lattice. The formamide moiety acts as... 

Two permanent merocyanines have been reported for the spiro-oxazines [85]. These were NOSH heteroanellated by imidazo [l,2-a]pyridine and imidazo [l,2-a]pyrimadine. Several tests have been conducted to determine the nature of these species. H -NMR data show that the indoline nitrogen is not highly charged and the crystal structure indicates that the ground state is essentially the quinoidal form. The most stable form was found to be the TTC isomeric form by x-ray analysis. The dipole moment of these permanent spiro-oxazine merocyanines was around 3.84 D, which is much lower than the values reported for spiropyran merocyanines. 

X-ray crystal structures for spirooxazolones including 4-spirocyclopropane 353 (m = 1, R2 = 4-spiro-(phenyl)cyclopropane 353 (n = 1, R2 = Ph), 4-spiro-... 

Section II. Haupt and Florke have reported the crystal structure of [In Re2(CO)6(/i-I) - Re2(CO)6(ji-I)2 ], which contains a spiro /i4-In bound to four rhenium atoms. This complex was obtained as one product from the reaction between Inl3 and [Re2(CO)10] at 437 K. [H. -J. Haupt and U. Florke, Acta Crystallogr., Sect. C. C45,1718 (1989)]. 

J. S. Leigh and K. H. Whitmire, Acta Crystallogr., Sect. C. C46,732 (1990)], which contain tetra-hedrally coordinated tin and lead atoms. Crystal structure data has been presented for [Sn Fe2-(CO)8) Fe3(CO)n ], which contains a tetrahedral, spiro, i/4-tin atom bridging the Fe—Fe bond in the Fe2(CO)8 fragment and one Fe—Fe vector in the triangular Fe3(CO)n unit [S. G. Anema,... 

Figure 1 Crystal structure of (R,R)-(—)-fraws-bis(hydroxydiphenylmethyl)-l,4-dioxa-spiro[4.5]decane 3c (courtesy of B. Szczesna).

V. Malatesta, R. Millini, and L. Montanari, Key intermediate product of oxidative degradation of photochromic spiro-oxazines. X-ray crystal structure and electron spin resonance analysis of its 7,7,8,8-tetracyanoquinodimethane ion-radical salt, J. Am. Chem. Soc., 117, 6258-6264 (1995). 

Gardmultine (C45H54N4O10) a bisindole alkaloid isolated from Gardneria multiflora Makino, comprises gardneramine and chitosenine linked by a spiro five-membered ring. The structure proposed from chemical and spectroscopic properties (50) was confirmed by the crystal-structure analysis (51). The structural formula and the stereodrawing, shown in Fig. 25, illustrate the spiro junction at atom C-16 between the two component alkaloids of gardmultine. 

Lastly, the cyclophosphazene ring conformation is almost identical to that found in other similar structures. The NPN angles range between 113.0(1) and 120.5(2)°, while the P—N bonds range from 1.554(3) to 1.634(3) A. This is to be compared to the crystal structure of SPIRO N3P3C1JHN —(CH2)3 —NH]30) for example. 

Dandia A, Singh R, Khaturia S et al (2006) Efficient microwave enhanced regioselective synthesis of a series of benzimidazolyl/triazolyl spiro [indole-thiazolidinones] as potent antifungal agents and crystal structure of spiro[3H-indole-3, 20-thiazolidine]-30(l, 2, 4-triazol-3-yl)- 2, 40(lH)-dione. Bioorg Med Chem 14 2409-2417... 

Ashida, M. Uyeda, N. and Suito, E. (1971). Thermal transformation of vacuum condensed thin films of copper phthalocyanines. /. Cryst. Growth, 8,45-56. [268] Ashizawa, K. (1989). Polymorphism and crystal structure of 2R,4S,6-fluoro-2methyl-spiro[chroman-4,4 -imidazoline]2 -5-dione(M79175). J. Pharm. ScL, 78, 256-60. [129]... 

Spiro-DAMP (27) was slightly more potent at Mg muscarinic receptors than at Mg receptors. It was proposed that the geometry of the spiro-molecule might reflect the receptor-bound conformation of 4-DAMP (26) this conformation differs from that observed in the crystal structure of 4-DAMP. 

Fig. 5. Calculated NMR chemical shift tensor (dark gray) in spiro-[C2H4(S)2]2Si (1) geometry of the crystal structure with spiro angle at Si of 74.4°. For better visualization the chemical shifts with respect to TMS = 0 ppm were used as principal values in ail tensor drawings.

Spiro compounds are also known, and the crystal structure of octamethylspiro (5.5) pentasiloxane has been determined. The planar rings lie in two mutually perpendicular planes. There is evidence that the methyl groups librate about the Si-0 bonds as if the Si atoms to which they are attached were free to move in a ball-and-socket joint. Data obtained include Si-0, 1-64 0-03 A, Si-C, 1-88 0-03 A, Si bond angles tetrahedral, Si-O-Si angles 130°. 

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