Peptidyl inhibitors of viral proteases

A compound of the formula ##STR24## wherein R.sup.1 is lower alkyl, halo-lower alkyl, cyano-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, aryl-lower alkyl, heteroaryl-lower alkyl, lower alkenyl or lower alkynyl;

• R.sup.2 is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, aminocarbonyl-lower alkyl or lower cycloalkyl-lower alkyl;
• and
• R.sup.3 is hydrogen or lower alkyl;
• or
• R.sup.2 and R.sup.3 together are di- or trimethylene optionally substituted by hydroxy;
• R.sup.4 is lower alkyl, hydroxy-lower alkyl, lower cycloalkyl-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, lower alkenyl, aryl or lower cycloalkyl;
• R.sup.5 is lower alkyl, hydroxy-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkyl, aryl-lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl or lower cycloalkyl;
• R.sup.6 is hydrogen or lower alkyl;
• R.sup.7 is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower cycloalkyl-lower alkyl or lower cycloalkyl;
• R.sup.8 is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl or aryl-lower alkyl;
• R.sup.9 is lower alkylcarbonyl, carboxy-lower alkylcarbonyl, arylcarbonyl, lower alkylsulphonyl, arylsulphonyl, lower alkoxycarbonyl or aryl-lower alkoxycarbonyl;
• and
• R.sup.10 and R.sup.1 l are each independently a lower alkyl, and wherein any carboxy, hydroxy or aminocarbonyl group present in the compound is protected.

A process for producing a compound of the formula:

• ##STR25## wherein E is CHO;
• R.sup.1 is lower alkyl, halo-lower alkyl, cyano-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, aryl-lower alkyl, heteroaryl-lower alkyl, lower alkenyl or lower alkynyl;
• R.sup.2 is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, aminocarbonyl-lower alkyl or lower cycloalkyl-lower alkyl;
• and
• R.sup.3 is hydrogen or lower alkyl;
• or
• R.sup.2 and R.sup.3 together are di- or trimethylene optionally substituted by hydroxy;
• R.sup.4 is lower alkyl, hydroxy-lower alkyl, lower cycloalkyl-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, lower alkenyl, aryl or lower cycloalkyl;
• R.sup.5 is lower alkyl, hydroxy-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkyl, aryl-lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl or lower cycloalkyl;
• R.sup.6 is hydrogen or lower alkyl;
• R.sup.7 is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower cycloalkyl-lower alkyl or lower cycloalkyl;
• R.sup.8 is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl or aryl-lower alkyl;
• and
• R.sup.9 is lower alkylcarbonyl, carboxy-lower alkylcarbonyl, arylcarbonyl, lower alkylsulphonyl, arylsulphonyl, lower alkoxycarbonyl or aryl-lower alkoxycarbonyl;
• which process comprises treating an acetal of the formula ##STR26## wherein any carboxy, hydroxy or aminocarbonyl group present in the acetal is protected, and R.sup.10 and R.sup.11 are each independently a lower alkyl;
• with a strong acid, thereby producing the compound.

A process for producing a compound of the formula ##STR27## wherein E is B(OH).sub.2

• R.sup.1 is lower alkyl, halo-lower alkyl, cyano-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, aryl-lower alkyl, heteroaryl-lower alkyl, lower alkenyl or lower alkynyl;
• R.sup.2 is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, aminocarbonyl-lower alkyl or lower cycloalkyl-lower alkyl;
• and
• R.sup.3 is hydrogen or lower alkyl;
• or
• R.sup.2 and R.sup.3 together are di- or trimethylene optionally substituted by hydroxy;
• R.sup.4 is lower alkyl, hydroxy-lower alkyl, lower cycloalkyl-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, lower alkenyl, aryl or lower cycloalkyl;
• R.sup.5 is lower alkyl, hydroxy-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkyl, aryl-lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl or lower cycloalkyl;
• R.sup.6 is hydrogen or lower alkyl;
• R.sup.7 is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower cycloalkyl-lower alkyl or lower cycloalkyl;
• R.sup.8 represents lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl or aryl-lower alkyl;
• and
• R.sup.9 is lower alkylcarbonyl, carboxy-lower alkylcarbonyl, arylcarbonyl, lower alkylsulphonyl, arylsulphonyl, lower alkoxycarbonyl or aryl-lower alkoxycarbonyl;
• which process comprises treating a substituted dioxaborolane of the formula ##STR28## wherein any carboxy, hydroxy or aminocarbonyl group present in the dioxaborolane is or is not protected, and Q is ##STR29## wherein R.sup.12, R.sup.13, R.sup.14 and R.sup.15 each are hydrogen or lower alkyl and R.sup.16 and R.sup.17 each are hydrogen or lower alkyl,
• with a strong acid when Q is (a) and with an alkali metal periodate when Q is (b), thereby producing the compound.