Spiro derivatives

Benzonitrile oxide reacted with 3-phenyl-4-benzylideneisoxazolinone to produce two isomeric spiro compounds (Scheme 153) (72MI41609,72MI41608). The reaction of benzonitrile oxide with ketene produced a spiro derivative (67MI41600) with allenes, bis(spiroisoxazo-lines) along with monoaddition products were formed (Scheme 154) (79JOC2796, 70CR(C)-(271)1468). 

Reaction of 5n,6,7,8,9,l l-hexahydropyrido[2,l-f ][l,3]benzothiazine-7,l 1-dione (47, X = S, R = H) and 2-amino-6-fluorobenzamidine dihydrochloride in boiling EtOH yielded a diastereomeric mixture of spiro derivatives 48 (X = S, R = H), which were separated by flash column chromatography (OOMIPl). 

The cycloadditions of cyclopentadiene 1 and its spiro-derivatives 109 and 110 with quinones 52, 111 and 112 (Scheme 4.20), carried out in water at 30 °C in the presence of 0.5% mol. of cetyltrimethylammonium bromide (CTAB), gave the endo adduct in about 3 h with good yield [72b]. With respect to the thermal Diels-Alder reaction, the great reaction rate enhancement in micellar medium (Scheme 4.20) can be ascribed to the increased concentration of the reactants in the micellar pseudophase where they are also more ordered. 

Glutarimides may be regarded as oxidized piperidines, and many drugs containing this moiety are sedatives and anticonvulsants. A spiro derivative, alonimid (105) is such a sedative-hypnotic agent. It can be prepared by K t-butoxide catalyzed biscyano-ethylation of phenylacetonitrile, leading to 101. Alkaline hydrolysis produces tricarboxylic acid 102 which is smoothly Converted to the glutaric acid anhydride (103) with acetic anhydride. Friedel-Crafts... 

The spiro-derivative (206) forms anhydrous complexes with larger alkali ions (such as K+). Such complexes appear to have a 2 1 structure of type (207) (Weber, 1979). For Li+, the hydrated complex [Li2L(H20)4]l2 [where L = (206)] is formed. The X-ray structure of this species reveals that it is essentially of type (207) except that the Li+ in each macro-ring coordinates to only three ether oxygens of the ring. Each Li+... 

Compound 197 has been treated with carbonyl-containing derivatives such as cyclohexanone and 3-methyl-l-phenylpyrazol-5-one, in refluxing ethanol containing some drops of piperidine as catalyst, in order to promote Michael additions leading to spiro derivatives 198 and 199, where an acetyl group has been eliminated during the process (Scheme 8) <2000FES641>. 

Two other well defined carboranes 55g and 76 (vide infra, Section 3.2.7) are present in the reaction mixture containing 64c (vide infra, Scheme 3.2-35). Although pure 55g could not be isolated, its solution-state structure follows from a complete set of NMR spectra [71b], This unusual carborane is a spiro derivative without precedence and belongs to the family of 2,3,5-tricarba-mdo-hexaboranes(7). Ab initio MO calculations and NMR data indicate that the boron atom linked to the C3B3-framework by an endohedral C-B bond takes part in the cluster bonding [71b] (similar to an endohedral C-H bond in the other carboranes 55). 

A detailed study of the electronic structure and optical properties was published for the spiro derivative of f-Bu-PBD, Spiro-PBD (40) [108]. The vibronic structure of the lowest energy absorption band is well resolved, in solution as well as in the amorphous him. The 0-0 transition is at 351 nm (3.53 eV), the 0-1 and 0-2 vibronic bands that have a higher oscillator strength, are at 336 nm (3.69 eV) and 318 nm (3.90 eV), respectively. The fluorescence spectrum of this compound is symmetrical to the absorption spectrum with a Stokes shift of 43 nm. 

The different hole injection and transport materials can be compared relative to TPD. The spiro derivative Spiro-TAD (36a) has a lower first oxidation potential that can be explained by the better resonance stabilization of the radical cation [87]. The material exhibits two successive one-electron oxidations (0.23 and 0.38 V vs. Fc/Fc+) and one subsequent formal two-electron oxidation (0.58 V) to the tetracation (Fig. 3.28). 

Interesting observations were made on the cyclization reactions of N-benzoyl-CM- and fram-2-aminomethyl-l-cyclanols 216 and 217 with P4S10. From the cm isomers the spiro derivatives 219 were the main products, while the cm thiazines 220 were the minor products. In the cyclization of... 

Application of 1,3-cyclohexanedione 103a (80CPB648) and dimedone 103b (89CB1323) gives the spiro derivatives of tatrahydrochromenes 217 (Scheme 81). 

The thione group of dithiazolethiones is a very reactive heterodipolarophile. In Scheme 18 are given cycloadditions with nitrile oxides <67BSF2239>, diphenylnitrilimine, and ethyl azidoformate <85JCS(P1)1205>. The primary adducts are spiro derivatives, but only compound (131), which is obtained from nitrile oxides is isolable at low temperature. All are decomposed to give respectively compounds (132)-(134) and occasionally nitriles and sulfur. Compound (134) reacts further with nitrilimine affording compound (135) which is also isolated. 

Several examples of direct ring phosphorus interaction with transition metals are now known [279-287]. For example, reaction of N3P3CI6 with Na2Fe2(CO)g affords a novel spirocyclic diiron octa carbonyl derivative (Scheme 25) [282, 283]. The diiron spiro derivative acts as a template for the construction of several transition metal clusters. Some of the other examples where ring phosphorus atom is involved in interaction with transition metals are summarized in Scheme 25. The ring phosphorus atoms in hydrido phos-phazenes, N3P3R4R H also coordinates to transition metals. This has been discussed in an earlier section (vide supra). 

Ring closure at the uracil 6-position also occurred with brominated aromatic derivatives 444 linked to the 6-position, to give benzopyrano[4,3-rf pyrimidine-2,4-dione spiro derivatives 445 <2004S1864>. 

Only structures pertaining to the saturated 1,2-oxathiane 2,2-dioxides have been published. The preferred chair conformer is preserved in both polycyclic <1989AGE202, 1998CEJ1480, 1996CC431, 1994JOC3687> and spiro derivatives <1998EJO2073> with the sulfone oxygens in pseudoaxial and pseudoequatorial orientations. 

This strategy has been extended to generate spiro derivatives from appropriate hydroxyalkylidene precursors (83BCJ2652). The salicylidene derivative (164) has also been similarly cyclized (84CL130I) by treatment with t-butyl hypochlorite to yield a mixture of diastereomers (Scheme 54). 

Alkylation of 3-methyl-1,2,4,5-tetrahydro-3//-3-benzazepin-2-one in THF-DMF solution containing sodium hydride, with primary and secondary alkyl halides and with a-bromoesters, results predominantly in 1-monoalkyl derivatives, whereas with w,w-dibromoalkanes, 1,1-spiro derivatives are formed (80T1017). Apparently, 6,7-dihydro-5//-dibenz[6,rf]azepin-6-one does not condense with benzaldehyde or with nitrosobenzene at the active methylene group (55JA3393). 

The ring size of the spiro derivatives on the one hand and the bulkiness of the open chain substituents on the other, are expected to have an opposite influence on the size of the O—P—O angle and thereby on the state of hybridization of phosphorus. These geometric factors thus influence the efficiency of phosphorus d-orbital participation. According to Schweig, maximum dy overlap occurs if the d orbitals are oriented at an angle of 45 with respect to the xy-plane of the ring. 

Whether a small 0-P—O angle (as in the spiro derivatives) raises the energy of the LUMO or lowers the energy of the HOMO (or some of both) cannot be concluded on the basis of present experimental information. 

When 151 is caused to react with terf-butyl chloride, a coupling occurs in high yield [Eq. (99)] the substitution seems neither to be an SN1 nor an SN2 reaction but was suggested to occur via an initial electron transfer from 151 to f-BuCl, followed by coupling of the two radicals [Eq. (99)].37 Anion 151 also reacts with carbon dioxide, forming a spiro derivative of malonic acid. 

The unsubstituted spirononadiene has been obtained from silicon atoms and the diene, albeit in low yield. However it results in better yield from methoxytris(trimethylsilyl)silane and the diene on photolysis. a-Elimination is non-specific but favours the methoxysilylene, addition giving the two silacyclopentenes (111) and (112) with buta-1,3-diene (Scheme 186). Pyrolysis with excess butadiene gives the spiro derivative, in support of the cyclosilylene intermediate (113 Scheme 187) (81JA7344). 

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