RU2137743C1 - Method of synthesis of (1 + 1)-adducts of c60-fullerene with norbornadiene and its 7-spirocyclopropane-substituted derivative - Google Patents

Abstract

FIELD: organic chemistry. SUBSTANCE: method involves reaction of cyclo-addition of norbornadiene or 7-spirocyclopropane bornadiene to C₆₀-fullerene in chlorobenzene or 2-methylthiophene medium at 160-180 C for 5 h in excess of norbornadiene and 7-spirocyclopropane norbornadiene up to 50-200 times. Under these conditions the yield of end substances is 80%. EFFECT: high selectivity of process, simplified procedure. 1 tbl, 16 ex

Description

The proposed method relates to organic synthesis, in particular to a method for producing (1 + 1) -ducts of C ₆₀ fullerene with norbornadiene of composition C ₆₇ H ₈ and its derivatives (elemental composition includes C ₆₇ H ₈ fragment).

A known method of producing a (1 + 1) adduct of fullerene C _{60 of} composition C ₆₇ H ₈ , which is based on the reaction of cycloaddition of not norbornadiene (NBD) and its valence isomer, quadricyclane (Q) (quadricyclane is obtained from NBD by the photochemical method) at 80 ^° C. for 5 hours in toluene (see end of description).

The yield of adduct (1) is 43%, 46% of unreacted fullerene C _{60 is} contained in the reaction mass. ((1). M. Prato M. Magini, G. Scorano, V. Luchini. J. Org. Chem., 1993, 58, 3613-15).

The interaction of fullerene C ₆₀ with U is non-selective, because another third isomer (~ 5%) was discovered in the reaction mass, the structure of which remained unclear [1]. It should be noted that, judging by the structure (1), it is a product of addition to (norbornadiene fullerene according to the scheme [2 + 2].

This method (prototype) has the following disadvantages:
1. Low selectivity of the reaction (43%) and low yield of the target product. Due to the incomplete conversion of fullerene, it becomes necessary to separate the isomers using an expensive and time-consuming method of high performance liquid chromatography.

 2. The method is preparatively uncomfortable and low-tech, because essentially, the process of obtaining (1) is a two-stage process, because one of the reagents: quadricyclane is an unstable compound and must be obtained immediately before the reaction by a complex method using UV irradiation of norbornadiene ((2) C. D. Smith, Org. Synth ., 1971, V. 51, P. 133-136).

Реакция осуществляется в среде серного эфира при комнатной температуре в течение 48 ч при УФ-облучении ртутной лампой (λ - 254 нм) в присутствии триплетного стабилизатора ацетофенона. Образующийся при этом квадрициклан из-за значительного внутреннего напряжения является нестабильным соединением. Он достаточно легко изомеризуется в менее напряженный норборнадиен. Особенно легко этот процесс (Q ---> НБД) проходит под действием катализаторов (кислоты Льюиса, кислоты Бренстеда, комплексы переходных металлов), а также термически (так, например, время полупревращения Q в НБД при 100^oC составляет 14 ч) ((3). В.А.Брень, А.Д.Дубоносов, В.Н.Минкин, В.А.Черноиванов. Усп. химии, 1991, 60 (10), 913-946). В частности, квадрициклан претерпевает изомеризацию в НБД при хранении в стеклянной посуде, что объясняется наличием на поверхности стекла силанольных групп

имеющих слабокислотные свойства [3]. Кроме того, для получения квадрициклана необходимо большое количество легковоспламеняющегося и взрывоопасного (из-за образования перекисей) серного эфира (для получения 1 кг Q необходимо 6,7 литров Et₂O).

The reaction is carried out in an environment of sulfuric ether at room temperature for 48 hours under UV irradiation with a mercury lamp (λ - 254 nm) in the presence of a triplet stabilizer of acetophenone. The resulting quadricycle due to significant internal stress is an unstable compound. It is quite easily isomerized into less stressed norbornadiene. This process is especially easy (Q ---> NBD) under the influence of catalysts (Lewis acid, Bronsted acid, transition metal complexes), as well as thermally (for example, the half-time of Q in NBD at 100 ^o C is 14 hours) ( (3) V.A. Bren, A.D. Dubonosov, V.N. Minkin, and V.A. Chernoyvanov, Usp. Chemistry, 1991, 60 (10), 913-946). In particular, quadricyclane undergoes isomerization in NBD when stored in glassware, which is explained by the presence of silanol groups on the glass surface

having slightly acidic properties [3]. In addition, to obtain quadricyclane, a large amount of flammable and explosive (due to the formation of peroxides) sulfur ether is necessary (to obtain 1 kg of Q, 6.7 liters of Et ₂ O are necessary).

 3. Significant reaction time. Given the stage of production of quadricyclane, the total duration of the process is (48 + 5) 53 hours.

A new method is proposed for producing (1 + 1) adduct C ₆₀ with norbornadiene of composition C ₆₇ H ₈ , as well as (1 + 1-adducts of fullerene with substituted norbornadiene, in particular, 7-spirocyclopropane derivative, which does not have the disadvantages of the prototype. cycloaddition to fullerene C ₆₀ norbornadiene or 7-spirocyclopropannorbornadiene (2) under special conditions, namely, in the environment of specially selected solvents, in particular chlorobenzene or 2-methylthiophene at elevated temperature (160-160 ^o C) for 5 hours in excess NBD and (2) up to 50-200 times. their conditions yields (1 + 1) adducts of fullerene with norbornadiene (3) and 7-spirotsiklopropannorbornadienom (4) reaches 80% (see. the end of the description).

 When carrying out the reaction in a medium of halocarbons (methylene chloride, chloroform, carbon tetrachloride) and aromatic hydrocarbons (benzene, toluene, xylenes), the yield (3.4) does not exceed 10-20%.

 It should be noted that the compounds (3, 4) obtained as a result of the interaction of NDB and (2) with fullerene are indeed (1 + 1) adducts, and compounds (1) and (3) have the same elemental composition, but differ in structure.

 The advantages of the invention over the prototype.

 1. One-stage and high selectivity of the process.

 2. The high yield of the target product is 80% (in the prototype 43%).

 3. The lack of stage chromatographic separation and purification of the target product. Economy of solvents, reduction of energy and labor costs.

 4. The versatility of the method: norbornadiene and its 7-spirocyclopropane-containing analogue react with fullerene under the selected conditions.

 5. Reducing the duration of the experiment from 53 to 5 hours.

 6. The use of affordable and inexpensive reagents of petrochemical origin (norbornadiene, chlorobenzene and 2-methylthiophene).

 7. The simplicity of the technological design of the process. The synthesis of the target products is carried out using standard equipment and standard techniques: heating, evaporation of the solvent.

 8. The possibility of reuse of reagents and solvents. Unreacted norbornadiene or (2) taken in a 50-200 fold excess can be easily separated by distillation and returned to the process.

 The method is illustrated by examples (1-16).

General procedure for the reaction of fullerene with norbornadiene and 7-spirocyclopropannorbornadiene (2)
10 mg (0.014 mmol) of fullerene C ₆₀ , 0.7-2.8 mmoles of norbornadiene or (2) and 6-12 ml of solvent (2-methylthiophene, chlorobenzene) were placed in a micro autoclave (V = 17 ml). The sealed autoclave was heated in an oil bath with stirring at 160-180 ^o C for 20 hours (see table 1).

Literature
1. M. Proto, M. Magini, G. Scorano, V. Luchini, J. Org. Chem., 1993, 58, 3613-3615.

 2. S. D. Smith, Org. Synth., 1971, V. 51, P. 133 '133-136.

 3 V. A. Bren, A. D. Dubonosov, V. N. Minkin, V. D. Chernoivanov. Usp. chemistry. 1991, 60 (10), 913-948.4

Claims (1)

A method of obtaining (1 + 1) -ducts of fullerene C ₆₀ with norbornadiene and its 7-spirocyclopropane substituted derivative, characterized in that cycloaddition to fullerene C _{60 of} norbornadiene or 7-spirocyclopropannorbornadiene taken in 50-200-fold excess, or in medium 2-methylthiophene at a temperature of 160 - 180 ^o for 5 hours

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