T 0870/94 24-06-1998

I. The appeal filed on 22 August 1994 lies from the decision of the Examining Division posted on 20 June 1994 refusing European patent application No. 90 309 122.1 (European publication number 414 476).

II. The decision of the Examining Division was based on claims 1 to 11 as annexed thereto. Claim 1 read as follows:

"1. A process for preparing a photochromic halogenated spiropyran compound having a hydrophobic alkyl chain, which process comprises reacting a photochromic spiropyran compound of the following formula (I)

wherein R is an alkyl group of 6 to 22 carbon atoms, and R1 and R2 independently represent halogen, a ketoalkyl group of 2 to 18 carbon atoms, an alkoxy group of 1 to 18 carbon atoms, a nitro group, a halogen atom or an alkanoyloxymethyl group wherein the alkanoyl moiety has 1 to 22 carbon atoms directly with a halogenating agent to obtain a halogenated spiropyran photochromic compound of the following formula (II)

wherein R, R1 and R2 have, respectively, the same meanings as defined above and Y represents fluorine, chloride, bromine or iodine provided that one to four halogen atoms are substituted at the 4' , 5' , 6' and/or 7' position of the indoline ring."

III. The Examining Division held that claim 1 of the then pending request did not involve an inventive step in the sense of Article 56 EPC, having regard to the following documents:

(1) Chemical Abstracts Vol. 88, ref. no. 105190 g (1978)

(2) Chemical Abstracts Vol. 83, ref. no. 147466 d (1975)

More particularly, the Examining Division considered that the problem to be solved was to provide a further process to halogenate the phenyl moiety (left-hand side) of the spiropyran derivative of formula (I) using a halogenating agent. Considering documents (1) and (2), these already taught this halogenation reaction on the phenyl ring of spiropyran derivatives. Therefore the Applicant's argument oriented towards the drawbacks of the N-alkylation with a long alkyl group of a halogenated indoline, which is the precursor of the spiropyran derivatives, had nothing to do with the problem to be solved. The Applicant's further argument that halogenated spiropyrans were generally prepared by introducing in a first step a halogen atom into an indoline ring followed by the further processing steps to achieve spiropyran derivatives, appeared to be erroneous in view of documents (1) and (2).

IV. The Appellant (Applicant) submitted amended claims 1 to 6. with the Statement of Grounds of Appeal filed on 31. October 1994. Independent claim 1 as amended differed from that underlying the decision under appeal essentially in that the substituent Y was restricted to two bromine or chlorine atoms in the 5'- and 7'-positions and that the reaction featured the use of N-bromo/chlorosuccinimide as halogenating agent at a reaction temperature of about 25 C for 0.5 to 3 hours.

The Appellant objected that the decision under appeal was issued after only one previous communication. Although not being regarded as a substantial procedural violation sufficient to merit refund of the appeal fee, he submitted that such a refusal would not be fully in accordance with the requirements of Articles 113(1) and 96(2) EPC.

Having regard to the substantial issues, the Appellant submitted that the Examining Division considered only claim 1 of the then pending request in the decision to refuse the application. Amended Claim 1 filed with the Statement of Grounds of Appeal, however, combined claim 1 of the previously pending request with claims 2, 3, 5 and 6. As a consequence of this amendment the invention now concerned the selective insertion of two bromine or chlorine atoms at the 5'- and 7'-positions of the spiropyran derivative (I), trihalo- and tetrahalo-compounds not being produced. This selectivity was achieved due to the reaction of N-bromo/chlorosuccinimide at the specific temperature of 25 C for 0.5 to 3 hours with the spiropyran derivative (I) having a large hydrophobic N-alkyl group. The Appellant argued that a person skilled in the art would not have predicted in advance that the process of the invention would exhibit such selectivity.

The Appellant submitted that document (1) disclosed a bromination process of spiropyrans having a N-methyl group and not a large N-alkyl group of 6 to 22 carbon atoms. The reaction was carried out in boiling CHCl3, i.e. 61.2 C, for 0.5 to 1 hour. These conditions gave monohalogenation at the 5'-position only and no substitution at the 7'-position. In contrast, according to the process of the present invention, substitution at both 5'- and 7'-positions was obtained at about 25. C. If the present process was conducted at 60 C a tetrahalogenated product would be formed. Furthermore document (1) contained no teaching regarding the reaction conditions to produce dihalo-spiropyrans. Thus, there would be nothing in this document which would have made it obvious to a person skilled in the art that the 5'- and 7'-substituted product with a hydrophobic N-alkyl group could be obtained at 25 C using the claimed process.

The Appellant stated that document (2) disclosed monohalo-spiropyran compounds and would teach nothing regarding the preparation of dihalo-compounds having large N-alkyl groups. Thus, the claimed subject-matter should be regarded as not obvious over document (2).

V. The Appellant requested that the decision under appeal should be rectified under Article 109(1) EPC and the appeal be allowed. In the absence of an interlocutory revision, he requested that the Board of Appeal remits the case to the Examining Division for further prosecution. If neither of these requests were granted the Appellant requested subsidiarily that the Board of Appeal allows the application on the basis of the new claims provided with the Statement of Grounds of Appeal. If the latter subsidiary request was not granted he made an auxiliary request that oral proceedings be held.