Regioselective ring-openings of epoxy alcohols bearing a diphenylphosphinoyl (Ph(2)PO) group give diols which can undergo stereospecific Horner-Wittig elimination. This method was used to make allylic alcohols, unsaturated beta-hydroxy sulfides, homoallylic alcohols and unsaturated amino acids, with control over their absolute (R,S), relative (syn,anti) and geometrical(E,Z) stereochemistry.

The synthesis of a series of 2-(5-fluoro-1H-indol-3-yl)ethyl spiropiperidines is described together with their tachykinin NK2 receptor affinities measured in a rat colon binding assay. Equivalent NK2 receptor binding affinity was observed for the spirooxazolidinone 3-benzyl-8-[2-(5-fluoro-1H-indol-3-yl)ethyl]-1-oxa-3,8-diazaspiro[4,5]decan-2-one (3a), the imidazolidinone 3-benzyl-8-[2-(5-fluoro-1H-indol-3-yl)ethyl]-1,3,8-triazaspiro[4,5]decan-2-one (3s), and the pyrrolidinone 2-benzyl-8-[2-(5-fluoro-1H-indol-3-yl)ethyl]-2,8-diazaspiro[4,5]decan-3-one (3t). Substitution in the phenyl ring of compound 3a produced no significant enhancement in NK2 binding affinity. Replacement of the phenyl ring in 3a with other aromatic rings resulted in a significant loss in binding affinity. Compound 3a was shown to be a potent NK2 receptor antagonist in guinea pig trachea where it also demonstrated 1000-fold selectivity for NK2 receptors over NK1. In the anesthetized guinea pig, compound 3a administered by the intravenous or oral route displayed potent and long-lasting antagonist activity against NK2 receptor agonist induced bronchoconstriction.

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Allylic phosphine oxides are epoxidised anti selectively by m-CPBA. but this selectivity can be reversed if the allylic phosphine oxide is also an allylic alcohol.

Collagenase is a zinc-dependent endoproteinase and is a member of the matrix metalloproteinase (MMP) family of enzymes. The MMPs participate in connective tissue remodeling events and aberrant regulation has been associated with several pathologies. The 2.4 angstrom resolution structure of the inhibited enzyme revealed that, in addition to the catalytic zinc, there is a second zinc ion and a calcium ion which play a major role in stabilizing the tertiary structure of collagenase. Despite scant sequence homology, collagenase shares structural homology with two other endoproteinases, bacterial thermolysin and crayfish astacin. The detailed description of protein-inhibitor interactions present in the structure will aid in the design of compounds that selectively inhibit individual members of the MMP family. Such inhibitors will be useful in examining the function of MMPs in pathological processes.

Optimisation of NK2 receptor affinity in a series of sulfur derivatives resulted in the identification of highly potent 5-fluoroindol-3-ylethyl[4-(phenylsulfinyl methyl)]piperidines. Further structure activity analysis led to GR 159897 an NK2 receptor antagonist which potently blocks agonist-induced bronchoconstriction in the guinea-pig when administered by peripheral and oral routes.

Allylic rearrangement of substitued 2-hydroxyalk-3-en-1-yl(diphenyl)phosphine oxides to 4-hydroxyalk-2-en-1-yl(diphenyl)phosphine oxides can be performed with total regio- and reasonable stereochemical control. Alternatively, the reduction of substituted 4-diphenylphosphinoylbut-2-en-1-ones shows remarkable 1,4-diastereoselectivity. All these reactions are directed by the diphenylphosphinoyl (Ph2PO) group.

A deletion - optimization strategy based on an initial heptapeptide lead structure 1 led to potent and selective neurokinin NK2 antagonists 5 (pKB=9.3) and 9 (pKB=7.9) of substantially reduced molecular size. Tetrapeptide 5 (0.1 μmol/Kg i.v.) potently inhibits NK2 agonist-induced bronchoconstriction in guinea-pigs. Whilst less potent than 5 in vivo, the dipeptoid 9 (5 μmol/Kg i.v.) had a significantly longer biological half-life (> 2 h), and provides a potential lead towards non-peptide analogues.

Incorporation of D-Pro9 into substance P related peptides is known to enhance neurokinin NK-2 receptor agonist potency and selectivity with respect to other neurokinin receptors. We now report that replacement of D-Trp9 by D-Pro9 in the nonselective neurokinin antagonist [Arg5,D-Trp7,9, Nle11]-SP(5-11) gave a partial agonist with NK-2 receptor selectivity. Further incorporation of Pro10 provided the weak but selective NK-2 antagonist Arg-Ala-D-Trp-Phe-D-Pro-Pro-Nle-NH2 (compound 4; NK-2 pKB = 5.9; NK-1 pKB = 4.7; NK-3 pKB less than 4.6). Addition of a suitable lipophilic N-terminal substituent (e.g. Boc, PhCO, cyclohexylcarbonyl) to this compound greatly enhanced NK-2 antagonist activity (compound 10, GR 83074; NK-2 pKB = 8.2), and combined with further optimization of the N-terminal amino acids, provided the extremely potent and selective NK-2 antagonist PhCO-Ala-Ala-D-Trp-Phe-D-Pro-Pro-Nle-NH2 (compound 34, GR 94800; NK-2 pKB = 9.6; NK-1 pKB = 6.4; NK-3 pKB = 6.0). Compounds of this class produced a potent inhibition of NK-2 agonist-induced bronchoconstriction in the anaesthetized guinea-pig.

The design and synthesis of potent and selective neurokinin NK-2 receptor agonists 12 (GR64349) and 31 are described, together with structure-activity relationships for related analogues. Compound 12 (EC50 = 3.7 nM at NK-2 receptors in the rat colon; selectivity > 1000- and > 300-fold with respect to NK-1 and NK-3 receptors, respectively) was derived by incorporation of a Gly-Leu gamma-lactam conformational constraint into the C-terminal region of the neurokinin A octapeptide analogue [Lys3]-NKA(3-10). Compound 31 (EC50 = 15 nM in rat colon) contains a novel fused-bicyclic constraint at the corresponding site in the substance P hexapeptide analogue [Ava6]-SP(6-11).

The syntheses of some 1-[(3,4-dichlorophenyl)acetyl]-2- [(alkylamino)methyl]piperidines and their activities as kappa-opioid receptor agonists are described. Selected structural modifications are made to the basic moiety and at the 2-, 3-, 4-, 5-, and 6-positions on the piperidine nucleus to enable structure-activity relationships to be delineated. As a result, some highly potent and selective kappa-receptor agonists have been identified. In particular, this has been achieved by introduction of oxygen-containing functionality into the 4-position of the piperidine nucleus or the 3-position of the pyrrolidinylmethyl side chain. Thus, 1-[(3,4-dichlorophenyl)acetyl]- 2-[[1-(3-oxopyrrolidinyl)]methyl]piperidine (10) possesses high activity in the rabbit vas deferens (LVD, kappa-specific tissue) (IC50 = 0.20 nM) and is a potent antinociceptive agent, as determined by the mouse acetylcholine-induced abdominal constriction test (MAC) (ED50 = 0.06 mg/kg, sc). The spirocyclic analogue 8-[(3,4-dichlorophenyl)acetyl]-7-(1-pyrrolidinylmethyl)-1,4-dio xa-8- azaspirol4.5]decane (39) showed exceptionally potent activity: LVD, IC50 = 0.10 nM; MAC, ED50 = 0.001 mg/kg, sc. Both 10 and 39 displayed high selectivity for kappa-opioid receptors over both mu- and delta-opioid receptor subtypes.

A series of trans-3-(6- and 7-substituted-decahydro-4a-isoquinolinyl)phenols and trans-3-(octahydro-4a-isoquinolinyl)phenols have been synthesized as potential opioid analgesics. Using a combination of in vitro and in vivo test systems, the receptor profiles of selected compounds have been assessed and in some instances distinguish between mu- and kappa-receptor agonists. In general, introduction of a 6-exocyclic methylene group into the trans-3-(decahydro-4a-isoquinolinyl)phenol system enhanced both antinociceptive activity and kappa-opioid receptor selectivity. For each series, analogues bearing an N-cyclopropylmethyl substituent exhibited greater kappa-receptor selectivity while N-methyl derivatives showed greater mu-receptor selectivity. The 7-substituted compounds (3b) were significantly less potent antinociceptive agents than their 6-substituted counterparts (3a), the octahydroisoquinoline analogues exhibiting intermediate activity. The axial 8-methyl-6-exocyclic methylene isoquinoline (20) is the most potent compound in the mouse abdominal constriction assay (ED50 = 0.05 mg/kg sc), whereas the equatorial 8-methyl isomer (16) was significantly less potent (ED50 = 3.3 mg/kg sc).

The tachykinin receptor agents are …

Acylation of Ph2P(O)Me with a lactone gives a Horner-Wittig intermediate with a Z-double bond protected as a Diels-Alder adduct with furan and hence (Z)-penta-2,4-dien-1-ol. Substituted (E)-penta-2,4-dien-1-ols are available by a more general route involving addition of enals to phosphine oxides, a regiochemically controlled allylic alcohol transposition, and a Horner-Wittig reaction. The geometry of only one double bond can be controlled.

AbstractThe 3‐methoxy‐10‐methylene‐6‐oxamorphinans (VI) are the key step for the preparation of the 10‐methylene‐, 10‐oxo‐ and 10α‐methyl‐6‐oxamorphinans (VIIa,b), (VIIIa,b) and (Xa,b).

AbstractThe octahydropyranopyridine derivative (VIIa) is synthesized starting from the readily prepared compound (I) as shown; the analogues (VIIb) are similarly obtained.

AbstractDas Phosphinoxid (I) ergibt mit Crotonaldehyd (II) isomere Addukte (III) und (IV).