C ₆₀ - (N, N- Tetrachloride Phthaloyl) Synthesis Dehydroabietylamine Derivatives Of The Anti-HIV Activity

Dehydroabietylamine is one of important modified products of rosin and the maincomponent of disproportionated rosin amine. It is widely used in many fields such as chiralresolution，papermaking，adhesives，paint，beneficiation，oil exploitation，medicine，pesticide，etc. It is a natural chiral compound with three chiral carbon atoms and possesses an aromaticditerpene structure with three rings as many natural drugs. Fullerene is the third allotrope ofcarbon. Since the discovery of C₆₀, various fullerene derivatives have been developed and theirapplications in the felds of material and biomedical sciences have been studied extensively.The study found that C₆₀derivatives exhibit a range of interesting biological activities,including inhibiting HIV-1protease, antitumor, inducing DNA photocleavage, and scavengingfree radicals. Among these fullerene derivatives C₆₀hybrids containing bioactive groups havereceived considerable attention in recent years. Many bioactive molecules, such as amino acids,peptides, nucleotide, sugars and steroids have been linked to C₆₀, and these C₆₀derivatives hasbeen proved to have different biological activities.In this paper, dehydroabietylamine reacted with tetrachlorophthalic anhydride to giveN,N-（Tetrachlorophthaloyl）dehydroabietylamine, which was introduced carbonyl on B ringthrough oxidation, and then functional groups such as nitro group, acetyl group, ester group,hydroxyl group and methoxy group were introduced on C ring by nitration, acetylation,oxidation, hydrolysis and substitution reaction, and so a series of dehydroabietylamine deri-vatives were synthesized. Subsequently, the condensation reactions of7-carbonyl of dehydro-abietylamine derivatives with p-tosylhydrazide yielded the corresponding dehydroabietylaminep-tosylhydrazones, followed by [1+2] cycloaddition reactions with C₆₀to yield C₆₀-N,N-（tetr-achlorophthaloyl）dehydroabietylamine derivatives. These C₆₀-N,N-（tetrachlorophthaloyl）dehy-droabietylamine derivatives were waterborne modified to increase their solubility in biologicalenvironment and their biological activities of anti-HIV-1reverse transcriptase and anti-HIV-1protease were tested. The research project can be expected to provide a reference for exploringand developing new rosinamine derivatives with potential biological activity. Following are theworks and results of our study.（1） Dehydroabietylamine was purified by the salt-forming reaction of disproportionatedrosin amine and p-toluenesulphonic acid. N,N-（Tetrachlorophthaoyl）dehydroabietylamine（2）was synthesized by condensation reaction of dehydroabietylamine and tetrachlorophthalicanhydride.（2） N,N-（Tetrachlorophthaoyl）dehydroabietylamine was transformed into N,N-（tetrachlo-rophthaloyl）-12-acetyldehydroabietylamine（8） by Friedel-Crafts acylation in the presence ofAlCl3, followed by oxidation with m-chloroperbenzoic acid to generate N,N-（tetrachlorophthal-oyl）-12-acetoxydehydroabietylamine（9）. Compound9was transformed into N,N-（tetrachloro-phthaloyl）-7-oxo-12-acetoxydehydroabietylamine（10）, N,N-（tetrachlorophthaloyl）-7-oxo-12-h-ydroxydehydroabietylamine（11） and N,N-（tetrachlorophthaloyl）-7-oxo-12-methoxydehydroabi-etylamine（12）, respectively, by C-7benzylic oxidation, hydrolysis and the reaction with CH3I.（3） C ring of dehydroabietylamine derivatives（2） was mononitrated with the milder clay-supported copper（II） nitrate（claycop） to afford a mixture of N,N-（tetrachlorophthaloyl）-12-nitrodehydroabietylamine（3） and N,N-（tetrachlorophthaloyl）-14-nitrodehydroabiethylamine（4）, aswell as N,N-（tetrachlorophthaloyl）-7-oxo-13-nitrodehydroabiethylamine（4）. This reaction has the advantages of milder and high safety due to the lower concentration of nitate ion releasingin the claycop system, compared with the traditional H2SO4-HNO₃mixed acid system.（4） The conventional methods for C-7benzylic oxidations involve the use of chromium（VI）reagents, such as CrO₃and Na₂CrO₄, in a mixed solvent of Ac₂O/AcOH, which led toconsiderable amounts of toxic effuents and afforded low yields （approximately10¹5%） in theC-7benzylic oxidations of N,N-（Tetrachlorophthaoyl）dehydroabietylamine（2）, N,N-（tetrachlo-rophthaloyl）-12-acetoxydehydroabietylamine（9） and N,N-（tetrachlorophthaloyl）-12-nitrodehyd-roabietylamine（3） because of their poor solubility in Ac₂O/AcOH. So we used an excess oft-BuOOH （8equiv） as an oxidant and CrO₃/pyridine mixture as a catalyst, the reaction mixturewas stirred for25h at room temperature in CH₂Cl₂, the yields of N,N-（tetrachlorophthal-oyl）-7-oxodehydroabietylamine derivatives （6,10and5） was68.5%、65.5%、38.1%,respectively. Compared with the traditional CrO₃or Na₂CrO₄oxidant, using t-BuOOH as theoxidant, the reaction is milder，the post-treatment process of products is more simple and theyields is higher, meanwhile it produce few toxic effuents and has a great significance inenvironmental protection.（5） The condensation reactions of7-carbonyl or12-acetyl of N,N-（tetrachlorophthaloyl）dehydroabietylamine derivatives with p-tosylhydrazide yielded N,N-（tetrachlorophthaloyl）de-hydroabietylamine p-tosylhydrazone derivatives（13¹8）. The choice of reaction solvent had agreat infuence on the yields. A mixture of benzene/ethanol（4:1） was used as the reaction solventand p-tolu-enesulphonic acid（0.09equiv） was added as a catalyst, giving a good effect.（6） p-Tosylhydrazone derivatives（13¹8） were reacted with NaOMe in pyridine for20minat room temperature. A solution of C₆₀in chlorobenzene was then added, and the mixture wasstirred for24h at70°C. A mixture of the monoadduct, higher adducts and unreacted C₆₀wasobtained and then purifed by column chromatography to give N,N-（tetrachlorophthaloyl）-7,7-C₆₀-dehydroabietylamine（19）, N,N-（tetrachlorophthaloyl）-12-nitro（or acetoxy, methoxy）-7,7-C₆₀-dehydroabietylamine（20,21,22）, N,N-（tetrachlorophthaloyl）-13-nitro-7,7-C₆₀-deisopr-opyldehydroabietylamine（23） and N,N-（tetrachlorophthaloyl）-12-ethyl-23,23-C₆₀-dehydroabie-tylamine（24）. N,N-（tetrachlorophthaloyl）-12-acetoxy-7,7-C₆₀-dehydroabietylamine（21） was hy-drolysed to afford N,N-（tetrachlorophthaloyl）-12-hydroxy-7,7-C₆₀-dehydroabietylamine（25）.According to the literature, C₆₀reacted with p-tosylhydrazones to afford [5,6]-open isomers or amixture of [5,6]-open isomers and [6,6]-closed isomers. In our experiment, no traces of the[5,6]-open isomer were found and the only isolated product was the [6,6]-closed isomer. Thus,the carbene mechanism is realised in this reaction. The target compounds were characterized byIR, UV-vis,¹H NMR,¹³C NMR, MALDI-TOF MS and elemental analysis.（7） Ethylenediamine reacted with C₆₀of N,N-（tetrachlorophthaloyl）-C₆₀-dehydroabiety-lamine derivatives（19²5） by addtion reaction, then the products were acidified to giveN,N-（tetrachlorophthaloyl）-C₆₀-dehydroabietylamine ethylenediamine dihydrochloride derivat-tives（26³2）. The target compounds were characterized by MALDI-TOF MS, and were themixture of1²different addition degrees of ethylenediamine.（8） In this paper, the bioactivities of water-soluble N,N-（tetrachlorophthaloyl）-C₆₀-dehydroabietylamine ethylenediamine dihydrochloride derivatives were also investigated, andthe anti-HIV-1reverse transcriptase and anti-HIV-1protease activities of the sythesized sevenwater-soluble N,N-（tetrachlorophthaloyl）-C₆₀-dehydroabietylamine ethylenediamine dihydro-chloride derivatives were tested by The National Center for Drug Screening. The test results showed that:①7,7-C₆₀-substituted derivative（26）,12-hydroxy-7,7-C₆₀-substituted derivative（30）and23,23-C₆₀-substituted derivative（32） showed relatively high anti-HIV-1reverse transcr-iptase activities, and their median inhibition concentration(IC₅₀) were3.01μg/mL,5.24μg/mLand4.32μg/mL, respectively. But the anti-HIV-1reverse transcriptase activities of12-nitro-7,7-C₆₀-substituted derivative（27）,12-acetoxy-7,7-C₆₀-substituted derivative（28）,12-methoxy-7,7-C₆₀-substituted derivative（29） and C ring deisopropyl-7,7-C₆₀-substituted derivative（31）were relatively low, their IC₅₀values were greater than8μg/mL.②All seven water-solubleN,N-（tetrachlorophthaloyl）-C₆₀-dehydroabietylamine derivatives presented a certain anti-HIV-1protease activities. In the7,7-C₆₀-substituted derivatives（26³1）, the anti-HIV-1proteaseactivity of7,7-C₆₀-substituted derivative （26） was highest, its IC₅₀value was7.80μg/mL,closely followed by12-acetoxy-7,7-C₆₀-substituted derivative（28）, its IC₅₀value was12.65μg/mL, and that of12-hydroxy-7,7-C₆₀-substituted derivative（30） was lowest, its IC₅₀value was112.87μg/mL. Three other derivatives,12-methoxy-7,7-C₆₀-substituted derivative（29）,12-nitro-7,7-C₆₀-substituted derivateive（27） and C ring deisopropyl-7,7-C₆₀-substituted derivative（31）, their IC₅₀value were respectively19.39μg/mL、29.50μg/mL and19.43μg/mL.Compared with that of7,7-C₆₀-substituted derivatives（26³1）, the anti-HIV-1protease activityof23,23-C₆₀-substituted derivative（32） is lower, its IC₅₀value was633.94μg/mL.