(12) Patent Application Publication (10) Pub. No.: US 2003/0096379 A1 Kilgore Et Al
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US 20030096379A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2003/0096379 A1 Kilgore et al. (43) Pub. Date: May 22, 2003 (54) METHOD FOR PRODUCING TRYPTAMINE Publication Classification DERVATIVES (76) Inventors: James L. Kilgore, Long Beach, CA (51) Int. Cl. ............................ C12P 13/22; C12P 17/10 (US); J. David Rozzell JR., Burbank, (52) U.S. Cl. ............................................ 435/108; 435/121 CA (US) Correspondence Address: (57) ABSTRACT CHRISTIE, PARKER & HALE, LLP 350 WEST COLORADO BOULEVARD SUTE 500 The invention relates to a coupled enzymatic process for PASADENA, CA 91105 (US) producing tryptamine derivatives from indole compounds. In the first enzyme-catalyzed reaction, indole derivatives are (21) Appl. No.: 10/112,253 converted to tryptophan derivative intermediates, then the tryptophan intermediates are decarboxylated in a Second (22) Filed: Mar. 28, 2002 enzymatic reaction in the same reaction System. In this way, Related U.S. Application Data tryptamine derivative products are formed from indole derivatives in a single process. The invention is also directed (60) Provisional application No. 60/279,876, filed on Mar. to novel tryptophan and tryptamine derivatives, which can 28, 2001. be prepared by the inventive method. US 2003/0096379 A1 May 22, 2003 METHOD FOR PRODUCING TRYPTAMINE 0007 All of the above-described synthetic routes to DERVATIVES tryptamine and tryptamine derivatives Suffer from known Side reactions, resulting in reduced yield, wasted Starting CROSS REFERENCE TO RELATED materials, and difficult purification Steps. AZiridine adducts APPLICATION also have a tendency to oligomerize to produce polyethyl enimine derivatives as a Side reaction. Nitroethylene and 0001. This application claims priority of U.S. Provisional other electron-deficient olefins participate in cycloaddition Application No. 60/279,876, filed Mar. 28, 2001, the entire side-reactions with indole and its derivatives. The indole disclosure of which is incorporated herein by reference. pyrrole ring itself is Susceptible to reduction in the presence of acids, which are often added to reactions when cyano and ACKNOWLEDGMENT OF GOVERNMENT nitro groups are reduced. De novo indole Synthesis is also SUPPORT complicated by Side reactions. For example, a Substrate for the direct formation of Sumatriptan by the Fischer indole 0002 This invention was made with government support Synthesis has been shown to form a closely-related dimeric under Grant No. 1R43 MH62244, awarded by the National impurity comprising about 11% of the isolated products. Institute of Health. The government has certain rights in the Sumatriptan is the most widely-Sold drug in its class, and a invention. Side reaction requiring careful chromatography to remove Such an impurity would add significantly to the cost of a FIELD OF THE INVENTION commercial process for its preparation. 0003. This invention relates to novel methods for pro ducing derivatives and to novel tryptophan and tryptamine SUMMARY OF THE INVENTION derivatives. 0008 Because of the drawbacks inherent in the chemical Syntheses of tryptamine derivatives, a Synthetic route based BACKGROUND on enzymatic catalysis offers an appealing alternative. Enzyme-catalyzed reactions are typically distinguished by 0004 Tryptamine derivatives are of interest for use as mild reaction conditions, Selectivity for the desired reaction, neuropharmaceuticals and as biological probes for the Study and few undesired side products. The present invention of neurologic phenomena. Tryptamine (indole-3-(2-etha relates to an enzymatic route for the production of ne)amine, which is frequently referred to as TNH) and tryptamine derivatives that combines the action of two 5-hydroxytryptamine (serotonin) are primary neurotransmit distinct enzymes. The combination of two enzymatic Steps ter molecules and are therefore of fundamental importance has the advantage of mild reaction conditions and few side in neurobiology. Functions of tryptamine derivatives include reactions, leading to the efficient production of a wide range regulation of diurnal cycles, Such as the onset of Sleep and of different substituted tryptamines. In another embodiment, the modulation of fertility in humans and other mammals. the present invention relates to novel Substituted tryprophan Neuroactive tryptamine derivatives frequently bear one or and tryptamine compounds. These novel Substituted tryp more Substituents on the amino nitrogen, as are found in tophan compounds can Serve as key precursors for the N-acylindolethylamines such as melatonin and the N,N- production of the corresponding tryprtamines and also as dimethyl groups of the “triptan” migraine drugs, Such as key pharmaceutical intermediates. The novel tryptamine Sumatriptan (ImitrexTM), rizatriptan (MaxaltTM), and Zomi compounds are useful as intermediates for the production of triptan (ZomigTM). neuroactive drugs and other bioactive molecules. 0005 Tryptamine derivatives may be produced by chemical Synthesis, Such as by attaching a 2-carbon chain to DESCRIPTION OF THE DRAWING a previously prepared indole derivative ("aminoethylation'), 0009. These and other features and advantages of the by Synthesizing an indole derivative that bears a Substituent present invention will be better understood by reference to at the C-3 position that can later be converted into an the following detailed description when considered in con ethylamino group, or by Simultaneously forming an indole junction with the accompanying figure wherein: ring and attaching the ethylamino group to the indole ring. Each of these synthetic routes has drawbacks in terms of the 0010 FIG. 1 is a DNA sequence of a synthetic gene Substituents that can be introduced, the length and complex derived from SuS Scrofa aromatic amino acid decarboxylase ity of the Synthesis, and the undesirable side products optimized for expression in E. coli, wherein the underlined formed during the Synthetic process. restriction sites are 5'-NcoI and 3'-BamHI. 0006. A number of methods are available for “aminoet DETAILED DESCRIPTION OF THE hylation, the attachment of a 2-carbon ethylamino group to INVENTION an indole ring. Reaction of an indole with a strong base, Such as a Grignard reagent, followed by reaction with aziridine 0011. The present invention is directed to a novel method directly gives the aminoethylated product in fair-to-moder for preparing tryptamine derivatives as well as to novel ate yields. Conjugate addition of an indole to nitroethylene tryptophan and tryptamine derivatives. In accordance with followed by reduction of the nitro group achieves aminoet the method of the invention, an indole derivative, i.e., a hylation in two steps, although the reduction conditions for substituted indole, is converted to an indole-3-(2-ethy the nitro group are not compatible with certain other func l)amine by two enzymatic reactions. In the practice of this tional groups. Three-Step procedures include the initial for invention, two enzymes are used which, in combination, mation of an indole-3-carboxaldehyde, followed by conden permit an efficient preparative process for tryptamine com sation with nitromethane and Subsequent reduction of both pounds bearing a wide range of Substituents from inexpen the double bond and nitro groups, as well as initial attach Sive precursors, Such as Substituted indoles, pyruvic acid and ment of a (dimethylamino)methyl group to form a gramine ammonia. derivative, followed by displacement with cyanide and 0012. The two enzymes used according to the inventive reduction of the resulting nitrile to the amine. methods for the production of tryptamine derivatives are a US 2003/0096379 A1 May 22, 2003 tryptophan-Synthesizing enzyme, which catalyzes the pro 0016 Alternatively, tryptophan-synthesizing and tryp duction of a Substituted tryptophan from a Substituted tophan-decarboxylating enzymes useful in the practice of indole, and a tryptophan-decarboxylating enzyme, which this invention can be obtain by the use of various molecular catalyzes the conversion of a Substituted tryptophan to the biology techniques, Such as mutagenesis, Shuffling, molecu corresponding Substituted tryptamine. The reactions cata lar breeding, and gene reassembly. These and related meth lyzed by the tryptophan-Synthesizing enzyme and the tryp ods can be used to create vast numbers of mutant versions tophan-decarboxylating enzyme can be carried out as Sepa of an enzyme encoded by a known gene, and then the mutant rate reaction Steps, with or without isolation of the enzymes can be Screened for the desired catalytic activity. intermediate Substituted tryptophan, or both enzymes can be Examples of gene shuffling, gene reassembly, and molecular used together in a Single reaction mixture to carry out the breeding are described in U.S. Pat. No. 5,605,793, U.S. Pat. biocatalytic Synthesis of a wide range of tryptamines. No. 5,811,238, U.S. Pat. No. 5,830,721, U.S. Pat. No. 5,837,458, U.S. Pat. No. 5,965,408, U.S. Pat. No. 5,958, 0013 AS used herein, a tryptophan-Synthesizing enzyme 672, U.S. Pat. No. 6,001,574, and U.S. Pat. No. 6,117,679, means any enzyme capable of catalyzing the Synthesis of a the disclosures of which are all incorporated herein by substituted tryptophan from a substituted indole in combi reference. Examples of methods for constructing large num nation with a precursor carboxylic acid having at least a bers of mutants are described in U.S. Pat. No. 6,001,574, 3-carbon chain that is C.C.- or C, B-disubstituted