Antiparasitic avermectin derivatives.

THE FORMULA COMPOUNDS: (FORMULA I) WHERE THE DISCONTINUOUS LINE IN POSITIONS 22 - 23 REPRESENTS A DOUBLE OPTIONAL LINK AND WHERE, OR R EXP1 IS A HYDROGEN OR OH AND THE DOUBLE LINK IS ABSENT, OR THE DOUBLE LINK IS PRESENT YR EXP1 IS ABSENT; R (SQUARE) ES = CH2 OR A FORMULA GROUP - (X) - C (R EXP5) = CHR EXP6; R EXP3 IS HO CH3; R EXP5 YR EXP6 ARE BOTH H; R EXP5 EN HYR EXP6 EN C1 - C3 RENT, OR EXP5 OR EXP6 EN HY THE OTHER IS PHENYL, HETEROARILO, C2 - C6 ALCOXICARBONILO OR A PHENYLL OR HETEROARIL REPLACED IN WHICH THE SUBSTITUTE IS FLUOR, CL4, CL4 - C4 ALCOXI, C1 - C4 ALQUILTIO, HIDROXI (C1 - C4) ALQUILO, CIANO, AMINOSULFONILO, C2 - C6 ALCANOILO, C2 - C6 ALCOXICARBONILO, NITRO, TRIFLUOROMETILO, TRIFLUORINE OCHL - CIO - ALKYL - C18 YX IS A DIRECT LINK OR A RENTING GROUP THAT HAS 2 TO 6 CARBON ATOMS THAT MAY BE IN LINEAR OR RAMIFIED CHAIN; THEY ARE ANTIPARASITARY AGENTS OF WIDE SPECTRUM WITH THE CONDITION THAT NI R EXP5 OR R EXP6 ARE BOTH HYDROGEN WHEN X IS - CH (CH3) CH2 - AND HAVE UTILITY AS ANTIHELMINTICS, ANTIECTOPARASITARIES, INSECTICIDES AND PROMOTED ANCIENT.