Synthesis and mass spectral fragmentations of new spiro heterocycles Mohammad Rahimizadeh, Ali Shiri, Mehdi Bakavoli * Department of Chemistry, School of Sciences, Ferdowsi University, Mashhad 91775-1436, Iran Received 14 March 2007 Abstract The reaction of dichlorodiphenoxymethane (2) with ortho-functionlized benzoic acids 1a–c yielded the spiro derivatives of bezodioxinone 4a, benzoxazinone 4b and benzodioxepinone 4c. The same reaction with 1,8-diaminonaphthalene afforded the spiro perimidine 6, while with 1,1 0 -binaphthyl-2,2 0 -diol gave the semi-cyclized derivative 2,2-diphenoxydinaphthodioxepine 8. # 2007 Mehdi Bakavoli. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. Keywords: Spiroorthocarbonate; Azaspiro compounds; Oxaazaspiro compounds Spiroorthocarbonates (SOCs) and related compounds have received a great deal of attention as monomers since on polymerization undergo minimal shrinkage [1–3]. These monomers are highly desirable in the field of materials such as dental fillings, high strength composites, precision castings and adhesives [4–7]. The synthetic routes to SOCs are varied and mainly consist of organotin compounds. Sakai et al. reported a novel multi-step synthesis of SOCs from organotin derivatives and carbone disulfide [8,9], while a group of other workers prepared SOCs by utilizing tetraalkylorthocarbonates and diols in the presence of p-toluenesulfonic acid as an acid catalyst [10]. Other approaches mainly involve cyclocondensation of diols with thiophosgene [11] or with dichlorodiphenoxymethane [12]. As an entry into the synthesis of new spiro heterocycles analogues of SOC, we have utilized the latter compound as a suitable quadro-functional electrophilic reagent. Our synthesis of the spiroorthocarbonates (SOCs) 4a–c is shown in Scheme 1. We envisioned that nucleophilic displacement of the chlorine atoms in dichlorodiphenoxymethane (2) with ortho-functionalized benzoic acids 1a–c should afford an intermediate 3 which was on further reaction with the second molecule of 1a–c would provide the desired SOCs analogues 4a–c, respectively. 2,2 0 -Spirobi[benzo][1,3]dioxine-4-one (4a) was obtained in 47% yield by treatment of salicylic acid (a) with dichlorodiphenoxymethane (2) in dichloromethane and pyridine. The structure of cyclized product was confirmed by spectral and analytical data. In the 1 H NMR spectrum, a multiplet at d 7.3 ppm is assignable to the protons of the phenyl nuclei. The IR spectrum exhibited two characteristic absorption bands at n 1750 and 1150 cm À1 belonging to C O and C–O stretching vibrations, respectively. The mass spectrum showed the expected molecular ion peak at 284. www.elsevier.com/locate/cclet Chinese Chemical Letters 18 (2007) 689–693 * Corresponding author. E-mail address: mbakavoli@yahoo.com (M. Bakavoli). 1001-8417/$ – see front matter # 2007 Mehdi Bakavoli. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. doi:10.1016/j.cclet.2007.04.020