How happens the serealization the data in the file blkxxxx.dat in the bitcoin
You are being confused three ways.

First, you need to be careful that some of your numbers in decimal, others are in hexadecimal: 77 decimal -> 4d hexadecimal (so: 77d -> 0x4d)

Second, you need to be careful that most numbers are stored in little endian notation, so 0x00000001 -> 0x01000000. Theymos' discussion why little endian is used.

Third, you have mixed up numbers from the Genesis Block and those from block 125552:

The Genesis block nonce 2083236893d converts to 0x7c2bac1d as hexadecimal not 0x42a14695. 

0x42a14695 is the nonce mentioned at https://en.bitcoin.it/wiki/Block_hashing_algorithm for Block 125552, not for the Genesis block.

Similarly, Nbits 486604799d is for the Genesis block, 0xf2b9441a is for block 125552. Timestamp 1231469665d is for the Genesis block, 0xc7f5d74d is for block 125552.