Abstract: A catalyst obtained by contacting (A) a compound of a transition metal of the group V of the Periodic Table represented by formula (I):R.sub.n M(O).sub.m X.sub.p .cndot.L.sub.

Abstract: High purity polyethylene glycol derivatives of formula (I) are useful as protein modifiers of interferons, t-PA, EGF, various hormones, etc. The thus modified protein has minimized antigenicity, prolonged plasma half life, or improved transfer to tissue. A novel process for preparing high purity polyethylene glycol derivatives is also disclosed.

Abstract: A polyethylene glycol derivative of the formula ##STR1## wherein R represents a lower alkyl and n represents an optional positive integer which renders the average molecular weight of the polyethylene glycol moiety about 1,000 to 12,000, a peptide modified by said polyethylene glycol derivative and a method for production thereof. The polyethylene glycol derivative (I) is capable of modifying the guanidino groups in peptides. The peptides modified by the polyethylene glycol derivative (I) are extremely stable, are considerably delayed in biological clearance (i.e. the durability is extended) and exhibit their physiological activities effectively over the long period.

Abstract: Polyethylene glycol derivatives of the formula ##STR1## wherein R.sub.1 and R.sub.2 are the same or different and each represents a lower alkyl, m and n are the same or different and each represents a positive integer and p is 0 or a positive integer, peptides modified by the polyethylene glycol derivatives, methods for producing them and use of the modified peptides. The peptides modified by the polyethylene glycol derivatives (I) of the invention, as compared with the corresponding non-modified peptides, show decreased antigenicity, are considerably delayed in biological clearance, and exhibit their physiological activities effectively over a long period, rendering them very effective as pharmaceuticals as well as drugs for animals.

Abstract: A polyethylene glycol derivative of the formula ##STR1## wherein R represents a lower alkyl and n represents an optional positive integer which renders the average molecular weight of the polyethylene glycol moiety about 1,000 to 12,000, a peptide modified by said polyethylene glycol derivative and a method for production thereof.The polyethylene glycol derivative (I) is capable of modifying the guanidino groups in peptides. The peptides modified by the polyethylene glycol derivative (I) are extremely stable, are considerably delayed in biological clearance (i.e. the durability is extended) and exhibit their physiological activities effectively over the long period.

Abstract: A process for the manufacture of a polypeptide (I) having the formula: ##STR1## which comprises steps of: (a) coupling, successively and in the order of the sequence of the polypeptide (I), the four protected fragments A, B, C and D or five protected fragments A, B, C, E and F,said fragment A by the formula, Leu-Gin-Asp-Ile-Met-Ser-Arg-NH.sub.2said fragment B by the formula, Gln-Leu-Ser-Ala-Arg-Lys-Leusaid fragment C by the formula, Arg-Lys-Val-Leu-Glysaid fragment D by the formula, Tyr-Ala-Asp-Ala-Ile-Phe-Thr-Asn-Ser-Tyrsaid fragment E by the formula, Ile-Phe-Thr-Asn-Ser-Tyrand said fragment F by the formula, Tyr-Ala-Asp-Ala being represented, respectively, and(b) eliminating, at the end of sequence, all the protecting groups to provide the polypeptide (I) which is active on the stimulation of the release of the growth hormone and thus is very useful as medicine for treatment of growth hormone deficiency disease and the like.

Abstract: Poly-.alpha.-olefin, for example, polypropylene, is produced by subjecting a feed containing an .alpha.-olefin having 3 or more carbon atoms, to a preliminary polymerization at 40.degree. C. or less in the presence of a catalyst which comprises (A) a solid catalytic ingredient prepared (a) by reacting a Grignard compound of the formula, R.sup.3 MgX wherein R.sup.3 =C.sub.1-8 alkyl and X=halogen, with a reaction product of an aluminium halide with an organic silicon compound of the formula, R.sub.n.sup.1 Si(OR.sup.2).sub.4-n, wherein R.sup.1 =C.sub.1-8 alkyl or phenyl, R.sup.2 =C.sub.1-8 alkyl, n=0, or 1 to 3, (b) bringing the resultant solid carrier into a first contact with titanium tetrahalide, (c) treating the resultant titanium-containing solid product with an organic acid ester, and, finally, (d) bringing the treated solid product into a second contact with titanium tetrahalide; (B) another catalytic ingredient consisting of a trialkyl aluminium of the formula, AlR.sub.3.sup.4 wherein R.sup.4 =C.sub.

Abstract: Poly.alpha.-olefin, for example, polypropylene, is produced with an excellent yield by bringing, in the presence of an organic acid ester, a feed, containing at least one .alpha.-olefin having 3 or more carbon atoms, for example, propylene, into contact with a catalyst which comprises (A) a solid catalytic ingredient prepared (a) by reacting a Grignard compound of the formula, R.sup.3 MgX wherein R.sup.3 =C.sub.1-8 alkyl and X=halogen, with a reaction product of an aluminium halide with an organic silicon compound of the formula, R.sub.n.sup.1 Si(OR.sup.2).sub.4-n, wherein R.sup.1 =C.sub.1-8 alkyl or phenyl, R.sup.2 =C.sub.

Abstract: Poly-.alpha.-olefin having an excellent H. I. is produced with an excellent yield by bringing, in the presence of an organic acid ester, a feed, containing at least one .alpha.-olefin having 3 or more carbon atoms, into contact with a catalyst which comprises (A) a solid catalytic ingredient prepared (a) by reacting a Grignard compound with an aluminium halide-tetraalkoxysilane reaction product, (b) bringing the resultant reaction product into a first contact with titanium tetrahalide, (c) treating the resultant titanium-containing solid product with an organic acid ester, and, finally, (d) bringing the treated solid product into a second contact with titanium tetrahalide, and; (B) another catalytic ingredient consisting of a trialkyl aluminium.