A comprehensive profile of brain enzymes that hydrolyze the endocannabinoid 2-arachidonoylglycerol

Endogenous ligands for cannabinoid receptors (“endocannabinoids”) include the lipid transmitters anandamide and 2-arachidonoylglycerol (2-AG). Endocannabinoids modulate a diverse set of physiological processes and are tightly regulated by enzymatic biosynthesis and degradation. Termination of anandamide signaling by fatty acid amide hydrolase (FAAH) is well characterized, but less is known about the inactivation of 2-AG, which can be hydrolyzed by multiple enzymes in vitro, including FAAH and monoacylglycerol lipase (MAGL). Here, we have taken a functional proteomic approach to comprehensively map 2-AG hydrolases in the mouse brain. Our data reveal that 85% of brain 2-AG hydrolase activity can be ascribed to MAGL, and that the remaining 15% is mostly catalyzed by two uncharacterized enzymes, ABHD6 and ABHD12. Interestingly, MAGL, ABHD6, and ABHD12 display distinct subcellular distributions, suggesting that they may control different pools of 2-AG in the nervous system.     

2-AG + 2 new players = forecast for therapeutic advances

In this issue of Chemistry & Biology, Blankman et al. identify new enzymes hydrolyzing the endocannabionoid 2-arachidonoyl glycerol (2-AG), increasing the complexity of endocannabinoid signaling in the brain, but also pinpointing additional therapeutic targets.     

Synthesis,radiolabeling and biodistribution of morphine glucuronide (mor-glu)

The aim of this study was to synthesize a glucuronide conjugated morphine derivative which could be labeled with ¹³¹I, as a radiopharmaceutical, and to investigate its radiopharmaceutical potential using biodistribution studies in male Albino Wistar rats. Morphine was extracted from dry capsules of the opium poppy (Papaver somniferum L.). It was conjugated with UDP-glucuronic acid by using UDP-glucuronyl transferase (UDPGT) enzyme rich microsomes, purified by high performance liquid chromatography (HPLC) and characterized by nuclear magnetic resonance (NMR), infrared (IR) spectroscopy and liquid chromatography mass spectroscopy (LC-MS/MS). Normal and receptor blockage biodistribution studies were performed in male Albino Wistar rats. The results of the tissue distribution studies showed that ¹³¹I labeled morphine glucuronide (¹³¹I-mor-glu) uptake in the small intestine, large intestine and urinary bladder was higher than in the other tissues of the rats in the blocked receptor and unblocked receptor. A greater uptake of the radio labeled substance was observed in the hypothalamus and mid brain than in the other branches of the rats’ brains.     

A new methodology for the oxidation of sulfides with Fe(III) catalysts

A variety of sulfides were converted to the corresponding sulfoxide derivatives with 70% t‐BuOOH (water) as the oxidant in the presence of catalytic quantity of Fe₂(SO₄)₃. The method described has a wide range of applications, involves simple work‐up, exhibits chemoselectivity/enantioselectivity and proceeds under mild reaction conditions. The resulting products are obtained in good yield within a reasonable time. Copyright © 2012 John Wiley & Sons, Ltd.     

A concise and general methodology for the complete asymmetric synthesis of the orthogonally protected 2-amino-1,3,4-butanetriols (ABTs)

A complete asymmetric synthesis of the orthogonally protected 2-amino-1,3,4-butanetriols I (ABTs: versatile four carbon chiral synthons) was accomplished via the regioselective asymmetric aminohydroxylation (AA) reaction and oxazoline chemistry in four to six steps from the starting olefin 1. The syn-vicinal amino alcohol functionality of I was installed by the regioselective AA reaction of the achiral olefin 1 in a single step, and the anti-vicinal amino alcohol functionality of I was derived from the syn-amino alcohol 2 by inverting the C2 hydroxy group stereochemistry through the formation and hydrolysis of the oxazoline 7. Thus, the present strategy represents the most efficient and general asymmetric synthesis of ABTs so far.     

A novel methodology for the synthesis of 1-desoxy-Δ-tetrahydrocannabinol (THC) analogues

A versatile and efficient sequence was developed for the synthesis of 1-desoxy-Δ⁸-THC analogues and is demonstrated by the synthesis of sulfonamide analogues with an acetylene group at the C-2^′ position in the side chain. In this procedure the 1-desoxy-Δ⁸- THC ring structure is built first and the synthesis of the side chain is then developed.     

Mild acetal cleavage using B-chlorocatecholborane in the synthesis of rearrangement-sensitive 2-arachidonoylglycerol

A mild method for the cleavage of an acetal to afford a rearrangement sensitive diol using B-chlorocatecholborane was developed for the synthesis of the endogenous cannabinoid neurochemical messenger 2-arachidonoylglycerol. The tendency for rearrangement of 2-arachidonoylglycerol to the corresponding 1-arachidonoylglycerol was precluded with this reagent. Features of the partial recyclization to an isomeric acetal provide mechanistic detail.     

Synthesis and preliminary study of 99mTc-mercaptoacetyl-triglycine (99mTc-MAG3) for radiolabeling of immune globulins

The synthesis of a complex molecule with its coordination center composed by a triamide monomercaptide tetradentate set of donor groups plus a phenyl-acetyl group as protector group of a sulphur atom is reported. This compound has been mixed with immune glubulin G, labeled with ^99mTc and purified by high resolution liquid chromathography (HRLC). The biological behavior of this labeled compound was evaluated with mice of Balb-C origin, showing the biological properties of a protein. This molecule might be another option for radio-immuno-scintigraphic analysis when using proteins of antigenic nature.     

Chemical assays of end-groups displayed on the surface of poly(ethylene terephthalate) (PET) films and membranes by radiolabeling

Poly(ethylene terephthalate) (PET) films and track-etched microporous membranes naturally display, on their surfaces, reactive chain-ends, i.e. carboxyl and hydroxyl functions. These were assayed by suitable activation (reaction with carbodiimide and tosyl chloride, respectively), followed by coupling with ³H-lysine and liquid scintillation counting of the sample-associated radioactivity. Values ranging between 5 and 30 pmol/cm² (open surface) of labeled end-groups were obtained, depending on the physico-chemical nature of the samples. Basic hydrolysis enriched the PET films with both types of endings (15–25 pmol/cm²). Reduction of films with the NaBH₄-catechol complex in tetrahydrofuran enriched their surfaces with hydroxyl groups. However, this procedure was not readily applicable to the surface modification of membranes; we observed an erosion effect that was confirmed by scanning electron microscope analyses. In contrast with the reduction process, the oxidation with KMnO₄ in 1.2N H₂SO₄ could be easily applied to the modification of either films or membranes; their surfaces were significantly enriched with carboxyl groups (15–50 pmol/cm²). This surface modification strategy has been used for the covalent coupling of adhesive proteins on PET membranes developed as supports for cell cultivation.     

Synthesis, radiolabeling and in vivo biodistribution of diethylstilbestrol phosphate derivative (DES-P)

Diethylstilbestrol (DES) is a well known, nonsteroidal estrogen with high affinity for the estrogen receptor (ER). Today DES is used to treat breast and prostate cancers. A phosphate derivative of DES [Diethylstilbestrol diphosphate (DES-P)] which is specific to tumor cells consisting alkaline phosphatase enzyme was synthesized and labeled with ^99mTc using tin chloride as reducing agent. In vivo biological activity of ^99mTc labeled diethylstilbestrol phosphate compound (^99mTc-DES-P) was examined by biodistribution studies on Wistar Albino rats. Statistical evaluation was performed using SPSS 13 program. The percentage (%) radiolabeling yield of ^99mTc-DES-P and quality control studies were done by Thin Layer Radio Chromatography (TLRC). Results showed that, ^99mTc-DES-P may be proposed as an imaging agent for ER enriched tumors such as uterus and prostate and their metastases in bones.     

An efficient procedure for the preparation of (E)-alpha-alkylidenecycloalkanones mediated by a CeCl(3) x 7H(2)O-NaI system. Novel methodology for the synthesis of (S)-(-)-pulegone

2-Alkylidenecycloalkanones are powerful synthons used as the key intermediates in many important syntheses. Because of their potential, a general method of preparation from readily available starting materials, under very mild conditions, was considered to be worthwhile. Cerium(III) chloride heptahydrate in combination with sodium iodide in refluxing acetonitrile promotes a regio- and stereoselective beta-elimination reaction to (E)-2-alkylidenecycloalkanones in 2-(1-hydroxyalkyl)cycloalkanones. The synthetic value of the present procedure is demonstrated by the synthesis of monoterpene (S)-(-)-pulegone (8) in its optically active form.     

A new methodology for monitoring the activity of cdMMP-12 anchored and freeze-dried on Au (111)

Matrix metalloproteinases (MMPs) are cell-secreted soluble and membrane-tethered enzymes that are capable of degrading extracellular matrix proteins, but also can process a number of bioactive molecules. They are involved in the cleavage of cell surface receptors, but are also thought to play a major role on cell behaviors as well as in diverse physiological and pathological processes, including embryonic development, wound repair, inflammatory diseases, and cancer. For these reasons, it is obvious that a control over MMPs activity is highly desirable. Consequently, the frantic search for new inhibitors has been coupled to the development of high-throughput methods able to rapidly screen the effect of possible MMP inhibitors on the activity of these enzymes. In this scenario, solid-state—based methods play a major role because of their compatibility with array formats that are able to extract more information from smaller sample volumes and offer some important advantages that are not available in the standard solution assays. In this work, the catalytic domain of MMP-12 was immobilized on a gold substrate and the surface coverage was measured by FT-SPR experiments. A new experimental procedure was developed to freeze-dry the anchored molecules and their activity was measured by ESI-MS. The kinetics parameters obtained for the immobilized enzyme are in good accordance with those reported for similar systems in solution. Inhibition of the immobilized molecules was also carried out, demonstrating the applicability of the method for rapid screening of MMP inhibitors.     

A total synthesis of (-)-hemiasterlin using N-Bts methodology.

A total synthesis of (-)-hemiasterlin has been accomplished in nine steps from 25(8) (>35% yield overall). An improved enantiocontrolled route to the tetramethyltryptophan subunit 32 was developed using an asymmetric Strecker synthesis (five steps, 50% yield from 25), and the dipeptide 22 was prepared in seven steps, 37% yield from valinol. The synthesis exploits the high reactivity of a Bts-protected amino acid chloride in the difficult peptide coupling of sterically hindered amino acid residues 18 and 20 to form 21 (70%, recrystallized) and also uses N-Bts intermediates for the high-yielding N-methylations of 14 and 31. In addition, the Bts-protected di-tert-butyl N-acylimidodicarbonate 33 is shown to undergo efficient coupling with 22 to form 34 (97% in the coupling step; 79% over the activation; coupling sequence from 32).     

Synthesis of covalent probes for the radiolabeling of the cannabinoid receptor

The main psychoactive constituent of marijuana, (-)-Delta(9)-tetrahydrocannabinol, produces most of its physiological effects by interacting with the CB1 cannabinoid receptor, a membrane protein belonging to the large superfamily of G-protein coupled receptors. The 3-D structure of the receptor binding site is of value in the design of novel medications for a variety of therapeutic indications. To obtain information on the amino acid residues associated with this binding site, we have designed and synthesized a cannabinergic CB1 ligand prototype carrying an electrophilic isothiocyanato group capable of reacting covalently with amino acid residues bearing thiol or unprotonated amino groups. The ligand also incorporates an iodide atom, which can serve as a high-activity radiolabel. The key step in our synthesis involves a rapid intramolecular Diels-Alder reaction of a transiently formed o-quinone methide, which proceeds stereospecifically with the formation of the tricyclic cannabinoid template. Introduction of the iodo group is the last step in the sequence and is compatible with the use of (125)I-radiolabel.     

One-pot preparation of 2-(alkyl)arylbenzoselenazoles from the corresponding N-(acetyl)benzoyl-2-iodoanilines via a microwave-assisted methodology

We report here the first example of a one-pot synthesis of 2-(alkyl)arylbenzoselenazoles from N-(acetyl)benzoyl-2-iodoanilines. The reaction was carried out in the presence of Woollins’ reagent under microwave irradiation and resulted in moderate to good yields.     

The 1 (2)A(1), 1 (2)B(2), and 1 (2)A(2) states of the SO(2) (+) ion studied using multiconfiguration second-order perturbation theory

The 1 (2)A(1), 1 (2)B(2), and 1 (2)A(2) electronic states of the SO(2) (+) ion have been studied using multiconfiguration second-order perturbation theory (CASPT2) and two contracted atomic natural orbital basis sets, S[6s4p3d1f]/O[5s3p2d1f] (ANO-L) and S[4s3p2d]/O[3s2p1d] (ANO-S), and the three states were considered to correspond to the observed X, B, and A states, respectively, in the previous experimental and theoretical studies. Based on the CASPT2/ANO-L adiabatic excitation energy calculations, the X, A, and B states of SO(2) (+) are assigned to 1 (2)A(1), 1 (2)B(2), and 1 (2)A(2), respectively, and our assignments of the A and B states are contrary to the previous assignments (A to (2)A(2) and B to (2)B(2)). The CASPT2/ANO-L energetic calculations also indicate that the 1 (2)A(1), 1 (2)B(2), and 1 (2)A(2) states are, respectively, the ground, first excited, and second excited states at the ground-state (1 (2)A(1)) geometry of the ion and at the geometry of the ground-state SO(2) molecule. Based on the CASPT2/ANO-L results for the geometries, we realize that the experimental geometries (determined by assuming the bond lengths to be the same as the neutral ground state of SO(2)) were not accurate. The CASPT2/ANO-S calculations for the potential energy curves as functions of the OSO angle confirm that the 1 (2)B(2) and 1 (2)A(2) states are the results of the Renner-Teller effect in the degenerate (2)Pi(g) state at the linear geometry, and it is clearly shown that the 1 (2)B(2) curve, as the lower component of the Renner splitting, lies below the 1 (2)A(2) curve. The UB3LYP/cc-pVTZ adiabatic excitation energy calculations support the assignments (A to (2)B(2) and B to (2)A(2)) based on the CASPT2/ANO-L calculations.     

A methodology for the synthesis of highly functionalized 2- and 4-aminoquinoline derivatives

A methodology for the synthesis of 2- and 4-aminoquinoline derivatives, which takes advantage of selective activation of 2- or 4-substituent of 2-methylsulfanyl-3-acyl-1H-quinolin-4-one 1, has been developed. Since a procedure for formation of 3-aminoquinolinones from the 4-quinolinone 1 was described previously, the new methodology comprises a general methodology for the selective syntheses of three isomeric 2-, 3- and 4-aminoquinoline derivatives starting with the common 4-quinolinone 1.     

New methodology for the synthesis of thiobarbiturates mediated by manganese(III) acetate

A three step synthesis of various thiobarbiturate derivatives 17-24 was established. The first step is mediated by Mn(OAc)?, in order to generate a carbon-carbon bond between a terminal alkene and malonate. Derivatives 1-8 were obtained in moderate to good yields under mild conditions. This key step allows synthesis of a wide variety of lipophilic thiobarbiturates, which could be tested for their anticonvulsive or anesthesic potential.