1. A process for the preparation of Latanoprost 1
38
which comprises deriving the compound 5
39
to give the compound 7
40
which is hydrogenated in the presence of catalyst to give the compound of the Formula 9
41
which is reduced with diisobutylaluminum hydride at temperature range from 50 to 50 C. followed by hydrolysis of the obtained reaction mixture under basic conditions to give compound 11, which is converted into latanoprost 1
42
werein one of R1 and R2 is an aryl carbonyl and the other one is selected from the group consisting of aryl carbonyl, acyl, trialkylsilyl, dialkylarylsilyl, 1-alkoxyalkyl, unsubstituted and alkyl-substituted tetrahydro-2H-pyran-2-yl and tetrahydrofuran-2-yl groups, and R3 is hydrogen when R1 is acyl and is equal to R1 when it is trialkylsilyl, dialkylarylsilyl, 1-alkoxyalkyl, unsubstituted or alkyl-substituted tetrahydro-2H-pyran-2-yl or tetrahydrofuran-2-yl groups; R4 is hydrogen when R2 is acyl and is equal to R2 when it is trialkylsilyl, dialkylarylsilyl, 1-alkoxyalkyl, unsubstituted or alkyl-substituted tetrahydro-2H-pyran-2-yl or tetrahydrofuran-2-yl groups.
2. A process according to claim 1 wherein the said reduction of the compound 9 with diisobutylaluminum hydride is provided at temperature range from 20 to 20 C.
3. A process according to claim 1 wherein the said catalyst contains palladium, platinum or nickel.
4. A process according to claim 1 wherein the said catalyst is palladium on carbon.
5. A process according to claim 1 wherein the said hydrogenation of the compound 7 is carried out in the presence of bases andor salts.
6. The process defined in claim 1, which comprises isolating the compounds of Formulae 7 and 9 in the course of the synthesis and, if desired, purifying them by re-crystallization.
7. Compound of the formula 7:
43
werein one of R1 and R2 is an aryl carbonyl group and the other one is selected from the group consisting of aryl carbonyl, acyl, trialkylsilyl, dialkylarylsilyl, 1-alkoxyalkyl, unsubstituted and alkyl-substituted tetrahydro-2H-pyran-2-yl and tetrahydrofuran-2-yl groups.
8. Compound of the formula 9:
44
werein one of R1 and R2 is an aryl carbonyl group and the other one is selected from the group consisting of aryl carbonyl, acyl, trialkylsilyl, dialkylarylsilyl, 1-alkoxyalkyl, unsubstituted and alkyl-substituted tetrahydro-2H-pyran-2-yl and tetrahydrofuran-2-yl groups.
9. Compound of the formula 11:
45
werein R3 and R4 are selected from the group consisting of hydrogen, trialkylsilyl, dialkylarylsilyl, 1-alkoxyalkyl, unsubstituted and alkyl-substituted tetrahydro-2H-pyran-2-yl and tetrahydrofuran-2-yl groups, and one of the R3 and R4 is hydrogen group.
10. (3aR,4R,5R,6aS)-Hexahydro-5-(p-phenylbenzoyloxy)-4-(3S)-5-phenyl-3-(tetrahydro-2H-pyran-2-yl)oxy-1E-pentenyl-2H-cyclopentabfuran-2-one 7a:
46
wherein PPB is p-phenylbenzoyl group and THP is tetrahydro-2H-pyran-2-yl group.
11. (3aR,4R,5R,6aS)-Hexahydro-5-(p-phenylbenzoyloxy)-4-(3R)-5-phenyl-3-(tetrahydro-2H-pyran-2-yl)oxypentyl-2H-cyclopentabfuran-2-one 9a:
47
wherein PPB is p-phenylbenzoyl group and THP is tetrahydro-2H-pyran-2-yl group.
12. (3aR,4R,5R,6aS)-Hexahydro-5-hydroxy-4-(3R)-5-phenyl-3-(tetrahydro-2H-pyran-2-yl)oxypentyl-2H-cyclopentabfuran-2-ol 11a:
48
wherein THP is tetrahydro-2H-pyran-2-yl group.
13. A process according to claim 1 wherein R1 and R2 are selected from the group consisting of benzoyl, p-toluoyl, p-phenylbenzoyl and tetrahydro-2H-pyran-2-yl groups, and at least one of the R1 and R2 is arylcarbonyl group.
14. A process according to claim 1, wherein compound 11 is converted into latanoprost 1 by reacting 11 with a metal salt of 5-(triphenylphosphoranylidene)pentanoic acid to form a compound of formula 13
49
wherein R3 and R4 are as defined above;
and when R3 andor R4 in compound 13 is other than hydrogen, removing the protecting group to yield latanoprost acid 13b
50
following esterifycation of compound 13b with compound 16:
(CH3)2CHX
wherein X is a leaving group, in the presence of a base to obtain latanoprost 1.
15. A process according to claim 14, wherein said base is cesium carbonate.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A channel shortening method for training a time domain equalizer comprising:
determining a first shortened channel impulse response for a communication channel using a first channel modeling scheme;
forming a time-mirrored image of the first shortened channel impulse response;
determining a second shortened channel impulse response for the time-mirrored image of the first shortened channel impulse response using a second channel modeling scheme;
combining the first shortened channel impulse response with an inverse of the second shortened channel impulse response to obtain a third shortened channel impulse response; and
employing the third shortened channel impulse response to configure a time domain equalizer.
2. The channel shortening method of claim 1, wherein determining a first shortened channel impulse response for a communication channel using a first channel modeling scheme comprises applying an auto-regressive moving average model using p1 poles and q1 zeros to form the first shortened channel impulse response having a first approximation H1(z)=B1(z)1+A1(z), wherein q1 is greater than a predetermined cyclic prefix length.
3. The channel shortening method of claim 1, wherein determining a second shortened channel impulse response for me time-mirrored image of the first shortened channel impulse response using a second channel modeling scheme comprises applying an auto-regressive moving average model using p2 poles and q2 zeros to form the second shortened channel impulse response having a second approximation H1(z)=B1(z)1+A1(z), wherein q1 is less than or equal to a predetermined cyclic prefix length.
4. The channel shortening method of claim 1, wherein the first shortened channel impulse response has a first approximation H1(z)=B1(z)1+A1(z) and the second shortened channel impulse response has a second approximation H2(z)=B2(z)1+A2(z), and wherein combining the first shortened channel impulse response with an inverse of the second shortened channel impulse response to obtain a third shortened channel impulse response comprises combining A1(z) and A2(1z) with appropriate delay.
5. The channel shortening method of claim 1, wherein the first channel modeling scheme is based upon a pole-zero model having p1 poles and the second channel modeling scheme is based upon a pole-zero model having p2 poles and wherein the number of taps in a channel shortening filter equals (p1+p2+1).
6. The method of claim 1, wherein the communication channel is an Asymmetric Digital Subscriber Line (ADSL) upstream channel.
7. An apparatus comprising a time-domain equalizer for equalizing a communication channel and training logic for training the time-domain equalizer based upon a training signal received over the communication channel, wherein the training logic is operably coupled to determine a set of coefficients for the time-domain equalizer using a two-pass auto-regressive moving average model.
8. The apparatus of claim 7, wherein the training logic comprises:
first channel modeling logic operably coupled to determine a first shortened channel impulse response for the communication channel;
inversion logic operably coupled to form a time-mirrored image of the first shortened channel impulse response;
second channel modeling logic operably coupled to determine a second shortened channel impulse response for the time-mirrored image of the first shortened channel impulse response; and
coefficient determination logic operably coupled to combine the first shortened channel impulse response with an inverse of the second shortened channel impulse response to obtain a third shortened channel impulse response.
9. The apparatus of claim 8, wherein the first channel modeling logic is operably coupled to apply an auto-regressive moving average model using p1 poles and q1 zeros to form the first shortened channel impulse response having a first approximation H1(z)=B1(z)1+A1(z), wherein q1 is greater than a predetermined cyclic prefix length.
10. The apparatus of claim 8, wherein the second channel modeling logic is operably coupled to apply an auto-regressive moving average model using p2 poles and q2 zeros to form the second shortened channel impulse response having a second approximation H2(z)=B2(z)1+A2(z), wherein q2 is less than or equal to a predetermined cyclic prefix length.
11. The apparatus of claim 8, wherein the first shortened channel impulse response has a first approximation H1(z)=B1(z)1+A1(z) and the second shortened channel impulse response has a second approximation H2(z)=B2(z)1+A2(z), and wherein the coefficient determination logic is operably coupled to combine A1(z) and A2(1z)) with appropriate delay in order to obtain the third shortened channel impulse response.
12. The apparatus of claim 8, wherein the first channel modeling logic is based upon a pole-zero model having p1 poles and the second channel modeling logic is based upon a pole-zero model having p1 poles, and wherein the number of taps the time-domain equalizer equals (p1+p1+1).
13. The apparatus of claim 7, wherein the communication channel is an Asymmetric Digital Subscriber Line (ADSL) upstream channel, and wherein the apparatus is a central ADSL terminal unit.
14. A program product including a computer readable medium having stored therein a computer program, the computer program for training a time-domain equalizer based upon a training signal received over a communication channel, the program product comprising:
first channel modeling logic programmed to determine a first shortened channel impulse response for the communication channel;
inversion logic programmed to form a time-mirrored image of the first shortened channel impulse response;
second channel modeling logic programmed to determine a second shortened channel impulse response for the time-mirrored image of the first shortened channel impulse response;
coefficient determination logic programmed to combine the first shortened channel impulse response with an inverse of the second shortened channel impulse response to obtain a third shortened channel impulse response; and
configuration logic operable to employ the third shortened channel impulse response to configure a time domain equalizer.
15. The program product of claim 14, wherein the first channel modeling logic is programmed to apply an auto-regressive moving average model using p1 poles and q1 zeros to form the first shortened channel impulse response having a first approximation H1(z)=B1(z)1+A1(z), wherein q1 is greater than a predetermined cyclic prefix length.
16. The program product of claim 14, wherein the second channel modeling logic is programmed to apply an auto-regressive moving avenge model using p2 poles and q2 zeros to form the second shortened channel impulse response having a second approximation H2(z)=B2(z)1+A2(z), wherein q2 is less than or equal to a predetermined cyclic prefix length.
17. The program product of claim 14, wherein the first shortened channel impulse response has a first approximation H1(z)=B1(z)1+A1(z) and the second shortened channel impulse response has a second approximation H2(z)=B2(z)1+A2(z), and wherein the coefficient determination logic is programmed to combine A1(z) and A2(1z) with appropriate delay in order to obtain the third shortened channel impulse response.
18. The program product of claim 14, wherein the first channel modeling logic is based upon a pole-zero model having p1 poles and the second channel modeling logic is based upon a pole-zero model having p1 poles, and wherein the number of taps the time-domain equalizer equals (p1+p2+1).
19. The program product of claim 14, wherein the communication channel is an Asymmetric Digital Subscriber Line (ADSL) upstream channel.